SPACE EXPLORATION CHALLENGES: ARE THEY SHOWSTOPPERS?

Transcription

1 : ARE THEY SHOWSTOPPERS? 1 Richard Heidmann Association Planète Mars heidmann.r@orange.fr ASTech Space Exploration Conference 17-19/12/2012 (doc. ESA)

2 2 Showstoppers: topics perceived as unmanageable in the frame of a realistic program More often: -problems are overstated -possible solutions are poorly surveyed Most prominently raised ones: -weightlessness -ionizing radiations -psychological issues -descent in Martian atmosphere -safety -costs considering those topics more positively is necessary to assess properly the project realism

3 WEIGTHLESSNESS 3 A space medical research pet subject -still going on after half a century -a way to make use of the ISS Strangely, the real question has been overlooked: -what are the effects of partial gravity? -ignoring the actual goals of exploration Bed rest test (doc. CNES) This could be investigated with: -a centrifuged tethered habitat in LEO -or even, a small centrifuge with mice, in the ISS (European Mars Society chapters proposal) The Translife project (doc. MIT)

4 WEIGTHLESSNESS Even for the most demanding Mars mission: -the 0g legs duration is limited to 6 months -which is the ISS nominal duration -where adequate countermeasures apply 4 But is it reasonable to land under less than optimal condition? This could be avoided with: -a centrifuged tethered habitat -with the transfer stage as counterweight An ESA sponsored study (doc. Delta-Utec) (doc. Manchu)

5 IONIZING RADIATIONS A serious concern, but the word in itself bears fear. 5 Facts: -level on Mars = ISS one -interplanetary level ~ 2 ISS -flux significant but not saturating -shielding against solar storms easy -but GCR shielding not practical (a 25cm water shield => dose/2) -with nominal data, the mission dose stay within with ISS regulations But data for HZE effects lacking: -this has been overlooked -but at last, labs are at work (doc. NASA/JPL) (doc. Simonsen) (doc. Mars Society) (doc. NASA) ASTech Space Exploration Conference 17-19/12/2012

6 IONIZING RADIATIONS 6 Data uncertainties need to be reduced: -some, on this basis, add 3σ margin -this certainly does not allow to conclude Research on biological effects should: -give away with such margins -lead to means to enhance cellular defense -and procure medical spinoffs Risk being statistical, programs compare in: # of crew * total dose over the 26 months missions period: ISS: 6 crew * ISS 6m * 4.33 times 6 months = 26 ISS 6m Mars 4Crew : 4*(4/6* ISS 6m * 2 + ISS 6m * 2 + ISS 6m * 3 + 2/6* ISS 6m * 2) = 28 ISS 6m preced. mission end outbound leg Mars stay 2 months of inbound similar astronauts population risk levels

7 PSYCHOLOGICAL ISSUES 7 A challenging matter, with few applicable data Not so much due to the mission duration in itself, but to duration + radical isolation Induced risks: -physiological & mental health issues -situation awareness -false judgments, mishaps -group behavior degradation -problems with ground control, etc. Difficult to evaluate. Make use of: -spaceflight experience (ISS, Apollo) -experience from Antarctic, subs -specific simulations (Mars500) Concordia Antarctic station Mars 500 (doc. ESA)

8 PSYCHOLOGICAL ISSUES Probably the field where: -feasibility is the most difficult to show -but, also, not so costly to scrutinize 8 Sustained efforts are needed: -studies of mission specific conditions -psychological effects -simulation campaigns in analog sites -selection process (individual & team) -training -habitat design -decision-making procedures -human factors related risk analysis Mars trek: relieving confinement stress Extraordinary individual accomplishments have demonstrated our ability to endure and adapt to extraordinary conditions Mars Society Utah analog (R.Heidmann)

9 DESCENT ON MARS (EDL) We know how to land ~1T P/L Landing 25-50T S/C is another problem which: -has long been understated -requires improved technologies and/or new ones 9 Some designs take large margins to cover uncertainties: -a 40 T TPS mass -a 15% descent propellant margin This leading to the titanic DRA5, a true project killer It has also be declared that a full generation will be required to make it Again, proceeding so crudely does not permit to conclude DRA5 (doc.nasa))

10 A lot of ways to solution: SPACE EXPLORATION CHALLENGES DESCENT ON MARS (EDL) 10 Devices scaling-up: -diameter & # of chutes -aeroshield diameter New devices: -deployable aeroshield -inflatable aeroshield -drag devices (ballutes) -higher L/D bodies (doc. Benton) Scaling-down the S/C by: -reducing the crew size (6 => 4) (also an efficient cost trimmer) -descending with 2 (smaller) modules (a concept overlooked) (Babakin Space Center) Mars Direct Light (doc. Mars Society)

11 SAFETY: A VERY SPECIAL PROGRAMMATIC ATTRIBUTE Crew safety is: -touchy to address -difficult to assess -impossible to measure 11 Mars mission conditions are stressing: -duration -isolation and remoteness -intrinsic complexity -environmental factors -human factors But there are means to build safety A ploc similar to Apollo (5%?) is: -an affordable goal -coherent with ESAS2005/Moon (2%) -acceptable with respect to the achievement Safe back home! (doc.nasa)

12 REINFORCING SAFETY THROUGH HUMAN PRESENCE 12 The problem of manned missions is the presence of humans But this improves safety! by allowing maintenance Reparability is a key for such a long mission, with so much HW / No spares A design revolution for space industry, mainly devoted to not repairable HW ISS shows that we have the skills dividing reparability by 2 degrades the catastrophic issues % (5.5 % to 9.1 %) (author Monte-Carlo simulations)

13 REINFORCING SAFETY THROUGH SMART MISSION DESIGN 13 A nightmare (Global Aerospace) Redundancies: -decisive (spares cannot be sent) -to what extent in the architecture: -Up to the top? (von Braun) -Split? ( free redundancy) Building mission robustness: -each phase gets a back-up Seeking for simplicity: -plethora of modules & of critical events kills the project (safety & cost!) -go direct! Abort to Mars: once perceived unsafe, Mars is more friendly than space (also save the mission) Mars Direct (doc. R. Zubrin)

14 COSTS Dev. & Ops costs: -are often comparatively overlooked -which results in taking high margins -and in confidence loss 14 To establish affordability, a project should: -show balance between motivations and budgets -present figures compatible with partners capabilities -not stand as an extraordinary proposal, but as a natural follow-on Problem mainly for the develop. cost, a Mars mission being possible only every 26 months (doc. APM)

15 COSTS 15 To establish confidence: -refer to detailed industrial project studies -make reference to past programs -take into account development hazards -justify that the project is adjusted to acceptable costs There exist means to adapt costs: -crew size -science equipment -planetary mobility means -and, of course, technologies readiness affordability first!

16 SUMMARY 16 Raised concerns are real, but ways of solution exist in each case: no real showstoppers Provided the political will, skills are in hand for project development Assessments are easily biased by: -preconception of risks -insufficient analysis -space policy general orientations -and even philosophical conceptions Particularly, we observe: -a tendency to overstate problems (cautiousness) -a skepticism about humanity future (disillusion)

17 SPACE EXPLORATION AND HUMAN SPECIES DESTINY 17 Balking the challenges is renouncing to escape our planetary confinement Our species has the unique capacity to escape its trap Should we miss this chance? Are we less gutsy than this cousin, who gnawed through his trapped arm?

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