Indian Space Programme Discussion

[Singha]

> Will glide to the nearest airport

autonomous Buran type swarm landings?

[member_28108]

It is so nice to say we have to have LOX CH4 etc work ion the new etc etc - we ahvent yet launched 4-10 Ton class payloads and so it is safer to pursue something which is proven.Of course the LOX CH4 engine is a research project but one has to walk before one can run the 4 minute mile.

[member_28108]

The SRB's were to be recovered by a parachute landing and the rocket core was supposed to be a fly back(to a runway)

[member_28108]

[Singha]

The pyro fasteners firing (faint whiff of smoke) as the giant SRBs liftoff slowly at full power

https://vimeo.com/21414718

excellent post. solid heavy-duty engineering, not some android app to home deliver ganja. the clean blue flame of the shuttle main engines resembles the sunflame burners of the AL31 we see.

[member_28108]

^
http://forum.nasaspaceflight.com/index. ... ic=10742.0

That's the engineer's response. Here's the astrophysicist's

Basically, in a LH2/LOX engine, you're creating a H+/O2- plasma in the combustion chamber, meaning the electrons are stripped from their atoms leaving an electron-ion soup. The hotter the plasma, the higher the transition energy as the electrons fall back back down to the ions, and that energy is released as light. The higher the energy, the bluer the light emitted. But the energy levels are quantised (thanks Max Plank), so only certain colours of light can be emitted. These are the spectra lines of Hydrogen (O2- and OH- have lines too, but they're in the infrared). Most LH2/LOX engines are very efficient, so they run very hot, and most the light emitted is in the ultraviolet, with a little bit in the blue and violet. For contrast, watch the H2 bleed-off flame on next STS night launch; it burns much cooler, and so has the bright red colour of the H-alpha line. Those bright orange flames around the pad on a Delta IV launch are also mainly due to H-alpha.

Liquid hydrocarbon also have those lines, but their colour is mainly the product of the microscopic particles of carbon soot glowing like a perfect blackbody (same deal as the filament in a light bulb). Because blackbody colour is not quantised, the colour of the soot (and thus the flame) becomes bluer as the temperature of the flame increases (as anyone who has used a gas stove will tell you).

The colour of the STS solids (bright white) is also due to microscopic soot, but this time it's made of Aluminum Nitrate crystals that have just been oxydised, and are glowing very hot, meaning most of the blackbody emission is in the UV, meaning they look bright white.

It's just rocket science.

Simon

[symontk]

^
http://forum.nasaspaceflight.com/index. ... ic=10742.0

That's the engineer's response. Here's the astrophysicist's

Thanks for the link Prasanna, one need to learn new things everyday

> Will glide to the nearest airport

autonomous Buran type swarm landings?

It will be a great win not just for ISRO but it will give confidence for India to develop safe passenger jet with autonomous operations

Lets think big

[Mort Walker]

GSAT-6 UPDATE:
GSAT 6 has been successfully positioned in its orbital slot of 83 Deg E and colocated with INSAT 4A, GSAT 12, GSAT 10 and IRNSS1C today (Sept. 06 2015) morning, after carrying out four drift arresting manoeuvers

Excellent excellent excellent!!!

Time for lungi dance.

[Hiten]

GoI produced this video about Team Indus' Moon mission

Using ISRO's Polar Satellite Lunch Vehicle [PSLV] it would, first, be placed in the Low Earth Orbit [LEO]. From there, it would coast towards the Moon, making use of gravity & on-board propulsion, & finally soft land on its surface. Once on the Moon, competition rules stipulates that it be able to travel at least half a kilometre on the surface, transmitting HD imagery back to Earth captured using its 3MP camera. The start-up intends to raise funds through a combination of equity financing, crowdsourcing & offering space for payload integration. The Google Lunar X Prize recently awarded it a Million Dollars, as prize money, for its simulated demonstration of Lander concept technology.

via http://www.aame.in/2015/09/team-indus-p ... ssion.html

[JE Menon]

FANTASTIC - Stuff is happening people!

Best part - Saad Nasser - determining mission trajectory from LV separation to descent orbit - 12 yrs old!!!

[kit]

^
http://forum.nasaspaceflight.com/index. ... ic=10742.0

That's the engineer's response. Here's the astrophysicist's

Basically, in a LH2/LOX engine, you're creating a H+/O2- plasma in the combustion chamber, meaning the electrons are stripped from their atoms leaving an electron-ion soup. The hotter the plasma, the higher the transition energy as the electrons fall back back down to the ions, and that energy is released as light. The higher the energy, the bluer the light emitted. But the energy levels are quantised (thanks Max Plank), so only certain colours of light can be emitted. These are the spectra lines of Hydrogen (O2- and OH- have lines too, but they're in the infrared). Most LH2/LOX engines are very efficient, so they run very hot, and most the light emitted is in the ultraviolet, with a little bit in the blue and violet. For contrast, watch the H2 bleed-off flame on next STS night launch; it burns much cooler, and so has the bright red colour of the H-alpha line. Those bright orange flames around the pad on a Delta IV launch are also mainly due to H-alpha.


So that's the reason early warning satellites use UV sensors to pick up rocket launches
Liquid hydrocarbon also have those lines, but their colour is mainly the product of the microscopic particles of carbon soot glowing like a perfect blackbody (same deal as the filament in a light bulb). Because blackbody colour is not quantised, the colour of the soot (and thus the flame) becomes bluer as the temperature of the flame increases (as anyone who has used a gas stove will tell you).

The colour of the STS solids (bright white) is also due to microscopic soot, but this time it's made of Aluminum Nitrate crystals that have just been oxydised, and are glowing very hot, meaning most of the blackbody emission is in the UV, meaning they look bright white.

It's just rocket science.

Simon

So that's the reason early warning satellites use UV Sensors to detect rocket launches .. even cruise missiles I think ..

[KrishG]

GoI produced this video about Team Indus' Moon mission

Wonderful! Hopefully GOI steps in and subsidizes the launch costs for Team Indus. I am waiting for them to announce the launch contract.

[akashganga]

GoI produced this video about Team Indus' Moon mission

Wonderful! Hopefully GOI steps in and subsidizes the launch costs for Team Indus. I am waiting for them to announce the launch contract.

Great video. Very inspiring to see young indians going boldly where no one has gone before. Hoping to see their craft land in moon soon. Cheers.

[sum]

^^ Total TFTA vid ( except for the 1st screenshot of the SDRE censor certificate )
Loved it and really inspiring to see.

[disha]

There are several posts I wanted to address individually., but consolidating it together in series of long posts.

If it meanders around a little bit., please stay the course patiently. Since I do believe that it answers several posts and tries to rest some assumptions being made.

Let me start with staging.,

STAGING

Right from the start of the space age., all the vehicles that go to the space are staged. Stacking them on top of each other like SLV is called sequentially stacked or stringing it together like ASLV or Space Shuttle, is tandem stacked. It is essentially stacked.

It has been speculated on this thread that multi-stage rocket are needed so that the rocket does not burn up. That is not the case.

One can design a rocket that has a sustained positive velocity and climbs ever so slowly., but generally up. Even if it climbs at the rate of say 10 km/hour., which is what some of the BRFites here can sprint sustainably., in 10 hours - the rocket is up in space. Where is the friction or the heat from friction to turn the rocket into ashes? There is none.

One can design a motor that takes a fraction of the energy of the GSLV's first stage or even the boosters and winch up a 1 tonne payload to 120 kms in space. So to get to space, one does not need much energy or speed or thrust. And one can go there ever so slowly.

So the contention that staging is used to overcome friction is false. The problem is not getting to space., as has been established that is easy. The problem is Staying IN space., that means the spacecraft has to go up and then fly horizontally. Actually even that is a misnomer. If you go to equator and fire a canon ball that travels at the speed of 8 Km/Sec (remember, the canonball is fired at the surface of the earth and the speed is relative to the earth's surface)., the canonball acheives orbit. It will circumnavigate earth and come back to its spot approx. 1 hr 24 mins. The only problem is that at the surface of the earth the atmosphere is dense and it will heat up the canonball. So you take it higher up, where there is not much of friction from atmosphere and kick it horizontally at @8 km/sec and it will orbit around the earth.

In a nutshell, it is easier to orbit a craft at 100 kms altitude since the craft will avoid most of the atmosphere and definitely some really tall buildings.

So again why the staging? If you noticed, the craft needs a horizontal kick of @8 km/sec to stay there. That is along with the craft that needs to be orbited, a kick engine has to be provided to give the craft a very good horizontal kick. In simple terms, one stage takes the craft up and the next stage kicks the craft out. That in a nutshell is your two stage rocket. But then PSLV is a four stage rocket and GSLV is a 3-stage rocket with 4-tandem boosters or in nominal parlance - a "seven staged" rocket!!

Why so many staging? For this., I have to introduce Newton's cradle. No not the cradle in which Newton was born., but the device that displays the conservation of momentum (see here: https://en.wikipedia.org/wiki/Newton%27s_cradle). Many have seen it., basically some steel (or very rigid) spheres (or balls) are hung in tandem from a wooden cradle. Pull one of the spheres up and let it go. When it impacts the rest of the spheres, the 5th or the last sphere at the other end goes up and comes down and impacts back and the first sphere goes up. (just watch the link!). The inbetween spheres remain static.

What this device is demonstrating is the convervation of momentum. Conservation of momentum holds in colliding or separating device. That is you can propel yourself in the opposite direction by ejecting a considerable part of your mass with sufficient velocity. So next time you go to a lavaratory after overeating., be careful and do observe conservation of momentum.

Hence in a staged rocket, by ejecting your boosters (tandem staging as in ASLV or space shuttle or GSLV) or lower stages (As in PSLV-Core alone or SLV)., one imparts a net positive velocity over a net time (accelaration) to the body "going up". In late 19th century., Russian scientist Tsiolkovsky figured it all out and derived an equation to tie it all together -> Delta V = Exhaust V * Ln m0/m1 where m0 is initial mass incl. propellant and m1 is the final total mass into orbit.

One can go through this paper to calculate the effect of staging (http://www.spaceatdia.org/uploads/maria ... e%2012.pdf) or plug Tsiolkovsky's equation into an excel spread sheet., and take the delta V for each stage and add it up to the next stage. The effect is adding a fourth stage to a rocket with three stages effectively increases the payload or for the same payload increases the final delta V.

In net., staging allows more payload for a given total propellant. It does not matter if the staging is sequential or tandem (tandem staging is considered stage 0 in a sequential form) to be orbited around Earth.

[SSSalvi]

The pyro fasteners firing (faint whiff of smoke) as the giant SRBs liftoff slowly at full power

https://vimeo.com/21414718

The fasteners seem to be blasting before the main engine ignition.

Later the thing lifts off slowly apparently due to to the main engine blast directed vertically down.

This is what is a feeling. Experts may comment pl.

[Singha]

I think there is enough talent in team indus and any contractors they engage to get the payload and mobility module done.

their main obstacles will be communication & propulsion - how they will monitor and give commands to exit the earth orbit, enter lunar transfer orbit, enter lunar orbit and enter lunar landing phase without a "deep space antenna" like isro has in byalulu which was specially setup for chandrayaan type work.

I see in the video a mockup of the propulsion engine(s) where it will fit - where they will source it from ? isro is perhaps only entity in india who has the knowhow to make both orbit correction rockets and such inter-planetary transfer rockets.

landing on moons surface is I believe easier as it lacks an atmosphere hence re-entry heating and turbulence issue is not there unlike earth or other gas covered planets like venus or (shiver) jupiter or saturn...temperature is also not extreme like venus or mars. but its sure a tricky business for a lander to do it automatically considering even isro has not sent a lunar lander yet.

[disha]

And, despite this ISRO goes back to 1960 and reinvents the kerosene-LOX engine (with special grades of rare to find blends of Kerosene etc rolled out as ISROrene).

Totally agree with the part., but ISRO is doing the semi-cryo or Kerosene-LOX for an altogether different reason*. By itself if you look at Ariane 5., there is no semi-cryo stuff.

Technically semi-cryo (or Kerosene-LOX) has no place in itself compared to LH-LOX or UDMH/HNO3 or solid state. However there are reasons like toxicity (UDMH/HNO3 is toxic) and scalability (ISRO does not have a giant ariane size or space-shuttle size LH-LOX engine currently).

Methox is NOT semi-cryo., it is another cryo-engine and it is needed for altogether different reason*. Instead of going up., methox is needed for bringing back from moon or mars or asteroids.

*I plan to discuss the benefits and drawbacks of various propellants in subsequent "long" posts.

[Raja Bose]

The pyro fasteners firing (faint whiff of smoke) as the giant SRBs liftoff slowly at full power

https://vimeo.com/21414718

excellent post. solid heavy-duty engineering, not some android app to home deliver ganja. the clean blue flame of the shuttle main engines resembles the sunflame burners of the AL31 we see.

Nobody can hit the nail on the head like Jernail Singha

[disha]

landing on moons surface is I believe easier as it lacks an atmosphere hence re-entry heating and turbulence issue is not there unlike earth or other gas covered planets like venus or (shiver) jupiter or saturn...temperature is also not extreme like venus or mars. but its sure a tricky business for a lander to do it automatically considering even isro has not sent a lunar lander yet.

Landing on moon is actually difficult since it lacks an atmosphere. One has to fire retro-rockets delicately to make the landing. This actually is tricky. What makes it easy is 1/6th the gravity., since one can have smaller thrusters.

[deejay]

FANTASTIC - Stuff is happening people!

Best part - Saad Nasser - determining mission trajectory from LV separation to descent orbit - 12 yrs old!!!

Isn't Sameer Joshi in the video a BRFite - Guardians of the Sky?

http://forums.bharat-rakshak.com/viewto ... f=3&t=6824

[hnair]

The pyro fasteners firing (faint whiff of smoke) as the giant SRBs liftoff slowly at full power

https://vimeo.com/21414718

The fasteners seem to be blasting before the main engine ignition.

Later the thing lifts off slowly apparently due to to the main engine blast directed vertically down.

This is what is a feeling. Experts may comment pl.

Most definitely not an expert, but this super-slo-mo sequence seem to show that SSME should achieve flame stabilization before, SRBs are lit. Probably because once the SRBs are lit and the SSMEs could not achieve full power, the SRBs cant be puffed out, unlike the SSMEs. Would be one hell of a disaster to deal with.

Looks like once SSMEs are purring along fine, both the fasteners blast and the SRBs are lit at nearly same time

https://www.youtube.com/watch?v=urxrOI6-RlE

[SSridhar]

hnair, IIRC, in the of GSLV, there a 4 or 5sec gap between the L40 strap-on ignition and the lighting up of the SRB. During this time, if enough thrust is not built up, the SRB is not lit up. We once had that situation too. The bolts cannot blast-off if there won't be enough thrust to clear the launch pad, I suppose.

[member_28108]

In a staged rocket where a liquid and solid enginrs are to fire the liquids fire first thrust confirmed and then solid engine fores. This is because once started a solid engine cannot easily be stopped nor throttled whereas of there is an issue with a liquid rocket it can be stopped

[hnair]

SSridhar, true. That was the very first, GSLV D1, 15 years back! The computers read a thrust anomaly in one and shut them all down. However some insulation started to burn and that needed fire suppressants. It was probably one of ISRO engineering's finest hours, when the smoke cleared, they swapped a spare booster in and launched again

http://www.thehindubusinessline.com/200 ... 296702.htm

Ten minutes before blast-off, the computer takes over. At four seconds before `time zero', it sends a command to ignite the four strap-on stages, which are rockets that cling to the lower end of the vehicle. In four seconds, these strap-ons should develo p enough thrust to support the lifting off of the vehicle. At `zero', the `core' is fired, and the rocket soars skywards.

Today, just one second before time zero, the computer gave a command to abort the take-off because it detected that one strap-on had not developed enough thrust.

Those watching the giant screen in the viewing room saw one strap-on catching fire and burning from top to bottom. Dr Kasturirangan explained that what actually burnt was only the insulating material.

IIRC, that incident and the calm response was much appreciated later in seminar circuits et al

[ManjaM]

GSAT6 Antenna successfully deployed. AOA! major step.

[JTull]

GSAT6 Antenna successfully deployed. AOA! major step.

Yes, it was done on Aug 30.

ISRO deploys S-Band Unfurlable Antenna of military satellite GSAT-6

The Indian Space Research Organisation (Isro) has successfully deployed the six metre diameter S-Band Unfurlable Antenna of military communication satellite GSAT-6 and also raised its orbit.

ISRO today said that it had deployed the S-Band Unfurlable Antenna of six metre diameter successfully.

The satellite was launched by ISRO's heavy rocket Geosynchronous Satellite Launch Vehicle-Mark II (GSLV) and was successfully placed into geo transfer orbit (GTO) on Thursday.

One of the advanced features of GSAT-6 satellite is its S-Band Unfurlable Antenna of six metre diameter - the largest satellite antenna realised by ISRO.

"This antenna is utilised for five spot beams over the Indian mainland, which exploit the frequency reuse scheme to increase frequency spectrum utilisation efficiency," said Isro.

[shaun]

there seems to be no plan for launching further iteration of RISAT series of satellites. RISAT 1 & 2 were launched 2012 & 2009 respectively.

[member_28108]

The unfurlable antenna technology will be a gamechanger and this will probably change the way we deploy such satellites and so things may change.Probably the next satellites will have still larger antennae (9-22 and who knows even 100 meters when GSLV Mk 3 is launched)

[member_29172]

Is the HLV (Heavy Lift Vehicle) confirmed for future production or is it still in design phase?

[member_28108]

^
http://www.thehindu.com/news/cities/Thi ... 262881.ece
The Indian Space Research Organisation (ISRO) is developing a series of heavy lift launch vehicles (HLV) capable of lofting satellites up to 10 tonnes into the orbit.

Mindful of the need to keep development costs under control, we have adopted a modular approach to the design of the HLV, Vikram Sarabhai Space Centre Director M.C. Dathan told mediapersons here on Friday. “While the GSLV Mk3, scheduled to undergo operation flight test in December 2016, will be capable of carrying satellites up to four tonnes, the standard size of satellites is expected to go up to six tonnes in the near future, requiring rockets with more heft,” he explained.

ISRO is toying with the idea of adding a semi-cryogenic stage to the GSLV Mk3 to generate a lift up to six tonnes. A more powerful cryo upper stage is expected to add the required muscle to handle satellites up to 10 tonnes. “What we have in mind is a progressive development to come up with need-based variants of the Mk3 instead of coming up with a new rocket altogether,” Mr. Dathan said.

Explaining the rationale behind the modular approach, he said the miniaturisation of electronics could lead to the development of lighter satellites requiring lesser lift capability. “This is where the modular design makes sense.”

Mr. Dathan said ISRO was developing an orbiter, lander, and rover for Chandrayaan-2, India’s second mission to the moon planned for 2017. “The initial proposal for a Russian lander was dropped after they changed the design, making it too heavy for the PSLV rocket.”

[vasu raya]

Explaining the rationale behind the modular approach, he said the miniaturisation of electronics could lead to the development of lighter satellites requiring lesser lift capability. “This is where the modular design makes sense.”

Are there any plans to introduce SoC in the GSAT series? heard about composite chassis though.

[ashish raval]

I think it is about time that ISRO shares its technology to private players like TATA/Mahindra/L&T. Although the pace of the development is good, I no longer feel that they will still have best brains compared to private industry which is gobbling up the best ones to improve pay per clicks algorithm or working on creating browsers. These guys should be working for nation to build rockets and satellites instead.

I was looking at rockets wiki page and could hardly see that Our rocket program as good as Ukraine and comparing that with the rockets built by Soviets, Europe and US, we are no where. Imagine the talent pool that these countries would have generated by these problems in Aerospace engineering. Think we need to expand ISRO 10x times and pay salary in par with private players.

People can disagree but I feel we still have long way to go catching up Top-4.

[disha]

^^ Ashish'ji we are in Top 3.

If you may want to measure space as a race.

Added later: No this is no jingoistic outburst.

[ashish raval]

^^ I would have loved to believe that disha ji but stats on wiki indicates otherwise. Please enlighten me otherwise.
https://en.m.wikipedia.org/wiki/Compari ... ch_systems

[sanjaykumar]

So they have a working scramjet.

[disha]

PREAMBLE:

^^ Ashish'ji.,

What are you comparing that says that ISRO is "fourth"? If you are just going by pure launch capacity to GTO, then it is like the proverbial seedless launches of a well endowed male.

Nobody is making the statement in the wikilink that you provided that ISRO is fourth or fifth or behind this or behind that to make a judgement call for you to declare that "People can disagree but I feel we still have long way to go catching up Top-4.".

The above statement is a red rag., to draw a rona-dhona response or if the rona-dhona response is not forthcoming, you can at least wag a finger in your righteous anger that at least you had a rona-dhona and in future will stand vindicated. And trust me, I am purposely getting baited by this response - since I am very tired of hearing such statements which amount to nothing other. Your statement is like the Daily mail headline "Kate middleton is either pregnant or not" - in short seedless missile tests which our western napaki neighbours regularly indulge.

So with not much ado and enthusiasm, again"catching up to Top-4" in what? Launch capacity to GTO? Or Launch capacity to Mars Or landing an experiment on moon and determining its water content? Or regular launch of humans to ISS?

--------------------------------------------------------------------------------------------------------------------------

You see., from wiki - you can get data. For analysis you still have to come here.

Launch capacity to GTO.

If the launch capacity to GTO is concerned., ESA/JAXA are well ahead. Russians are uninterested since for them GEO do not matter! Yes Russians need communications satellite and hence they use the Molniya orbits. Here is a wiki link on Molniya orbits https://en.wikipedia.org/wiki/Molniya_orbit. (See Errata below for commercial communication sat launches by Russia using Zenit).

They do have the capacity - of course. Does ISRO wants to use it? Maybe. But most likely not, since it is going to be costly to use Russian space stations to do that. (Clarifications, Russians themselves use the Molniya orbits)

Human spaceflight
If the launch capacity for safely launching humans to space (and retrieving them back) is the measure., then Russians are waaaay ahead and remotely followed by US (currently US does not have any human rated space vessel). And there are only two space faring nations which have that capacity. Chinese do not count, at most they have some 5 launches. ISRO will get there soon, if that is a priority.

Deep Space
If research into deep space is a count., then it is NASA, ESA, JAXA and ISRO. Chinese do not have any worthwhile deep space experience. Russians are having a string of bad luck here with the sad demise of fobos-grunt. Where is China? Well they do have a lander and a rover on Moon and that is impressive. Deep space requires a different kind of experience.

I have a sneaking suspicion that the Chinese inertial guidance systems are not par for the course., definitely not in the same league as the others mentioned above. Time will tell.

Propulsion Tech
If propulsion technology is the count., then it is again Russia, ESA, NASA, JAXA and ISRO. Chinese do have impressive capacity., but it revolves around the UDMH/NO4. They do not have any solid stage that can be discussed worthwhile. Neither they are ahead of ISRO in cryogenic systems.

Launch Systems
Launch systems. This is interesting., since launch systems can be thought of a single-gear trucks or multi-gear trucks with differential gears. Philosophy plays a large part here., but certain decisions taken in 1970s and 1980s when some of the forumite members were not even born and some were in their prime young come to bear now.

ISRO may not have the mightiest of the launcher, but it has developed an enviable track record of simultaneous precision launches and further very configurable launches.

In that sense Chinese launchers are specific and targeted. Trying to configure them will lead to "gust of winds" causing launch failures (check that out yourself on wiki).

See my suspicion above about precision injections? Yes., that plays the part. In very crude term carrying around a big "thing" does not matter much if you do not know where to put it!!!

Now there are other space sciences which I have not touched. For example landing on Mars and operating a rover there (only NASA has done it) or running a telescope in space (NASA again) or keeping the cosmonauts the most longer and healthier in space (Russia) or space environmental sciences (NASA, Russia)., the list is endless.

I took various parameters to explore space., and want to caution that it is not a "race" which any one nation or agency will win anytime soon. It will be a constant exploration and will take a whole lot of fortitude and courage.

Given the above., where does Chinese figure out most in space? They are an advanced space faring nation but ISRO is more respected than Chinese when it comes to space faring.

And nobody considers Ukraine as a space faring nation. It is a basket case running out of steam and living on borrowed soviet space research which the Chinese are very much interested in since they are not confident about it themselves. Brazil gets more respect than Ukraine when it comes to space sciences - so bringing in Ukraine as a point for comparison basically demeans this discussion totally.

[disha]

ERRATA: In the above, I incorrectly claimed that Russians are uninterested in GEO launches. I was wrong., Russians have the Zenit launch vehicles which are launched from either Baikanour or from their Odyssey launch platform for commercial launches.

And Russians do have a space telescope, I think SPEKTR. .

[Singha]

ideally in HLV there should be a clean base fat rocket with no strap ons and then configs of 2, 4 and 6 identical strap ons tailored for payloads.

being a clean design 30 yrs after the GSLV config was conceived in mid 80s, this is a chance to right historical wrongs and piggyback on whatever has been learnt in last 30. more tech is now COTS also...was not in that era.

[member_28108]

^ Not necessarily. Take Ariane 5 and Delta 4 heavy.