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How Could ISRO Move Toward Reusability? by sanman on 11 Oct, 2011 03:54
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We've all seen the nice video from SpaceX which accompanied their announcement of their Grasshopper testbed program, which will see a Falcon9 1st-stage lift off and land reusably, as part of a test regime.
While SpaceX's Grasshopper testbed may be limited to reuse of a 1st-stage for the time being, the video envisioned the potential for a reusable upper stage achieving re-entry with heat shield.
So you could say that SpaceX appears to want to prove reusability from the bottom up, starting with tests on a reusable 1st-stage first.
I'm wondering if it might be possible for ISRO to make a move towards reusability testing, but from the top down. By this, I was thinking that after ISRO fully proves its Cryogenic Upper Stage across repeated flights, that perhaps it might be nice to try to make this Cryogenic Upper Stage reusable, by endowing it with a heat shield to survive re-entry, as well as landing control systems to achieve a powered landing. Thus, such a successfully returned Cryogenic Upper State might possibly be refurbished for re-use on further flights.
ISRO has always emphasized its desire to do more with lower budgets, keep costs down, etc. It's with this in mind that ISRO has talked about a small shuttle-like RLV demonstrator, etc. A reusable Cryogenic Upper Stage would help to achieve the goals of cost reduction.
The successful SRE-1 and SRE-2 (Space Recovery Experiment) missions have shown that India's heat shield technology works for re-entry from LEO. It will also have to be proven for a future manned Indian space capsule. Use of this technology on a Cryogenic Upper Stage could then further the goal of reusability and cost reduction.
What is the feasibility of this idea? How much modification would have to occur for the Cryogenic Upper Stage to achieve reusability? -
#1 by Enthalpy on 13 Nov, 2011 01:23
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My thoughts about reusable stages: the sailback booster
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2554
The pressure-fed oxygen-methane is sturdy, easy to develop, looks easy to reuse, and yet has good performance. Sailing back needs less technology and added mass than flying back, and combines well with the pressure-fed stage.
I feel reuse easier at lower stages.
If I were to develop a stage in a country relatively new to space, I'd choose this pressure-fed oxygen-methane, rather than storable or pumped propellants.
Marc Schaefer, aka Enthalpy -
#2 by Enthalpy on 13 Nov, 2011 15:52
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Here are a couple of launcher examples, to illustrate the good performance of pressure-fed methane boosters. The upper stage uses the India-available RD-56 for performance.
These, and more examples, are described in detail there
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2554
Marc Schaefer, aka Enthalpy
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#3 by Enthalpy on 13 Nov, 2011 16:08
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Pressure-fed methane fits re-use well, to my eyes, because:
- Oxygen, methane and helium tanks can build a single strong hull of welded steel
- The tanks float, build a strong ship, stay clean and are quickly refilled
- The parachute that splashes the booster gently into the Ocean can sail it back to the launch site
- Remaining helium can inflate the parachute-kite to keep it up
Sailing back has some advantages (and a few drawback as usual) over flying:
- No difficult, heavy and unreliable wings, atmospheric propulsion, landing gear
- No airworthiness certification, no integration in the air traffic
- Failure to sail back doesn't destroy the booster
Automatic kite steering to pull a cargo ship exists at a company in Hamburg.
Marc Schaefer, aka Enthalpy
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#4 by JSz on 14 Nov, 2011 20:27
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The successful SRE-1 and SRE-2 (Space Recovery Experiment) missions have shown that India's heat shield technology works for re-entry from LEO.
Are you sure the SRE-2 mission was successful or it was performed?