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BIG risks of the Orion's "butterfly" solar panels
One of the most interesting and curious parts of the Orion is the "butterfly" shape of its solar panels, but, that kind of design is also a BIG RISK for the astronauts' LOC (Loss Of Crew) and for the (very expensive) lunar Orion's LOM (Loss Of Mission).
The solar panels of the Orion certainly are an improvement compared with the (fuel-cell only) Apollo since, thanks to the solar energy, the new capsule will have a six+ months stand-by life, so, it should wait in lunar orbit while the astronauts will accomplish some very long lunar surface missions.
But, the same solar panels (if damaged) could become a BIG risk for (both) the astronauts and the mission since the new capsule will have no fuel-cells but rechargeable batteries that need a countinuous energy source (and, it's useless to explain WHY that energy is VITAL for the LIFE aboard).
In other words, EVERY moon mission (priced around $8-10 billions each, all inclusive + inflation and cost growt!) could fail if this (little, low cost, but very important) part of the Orion will not work (or don't work properly).
The main risk of damage could happen at the Ares-I 2nd stage SM fairing separation, but other (possible) risks of damage may occur with a (wrong) Orion/LSAM rendezvous (before the TLI and after the lunar surface mission) at the TLI acceleration and LOI braking (if their mechanical support will fail) and at EVERY possible Orion's maneuver (maybe, to/from a future Lunar Space Station or refuel station).
Clearly, the probability of a solar panels damage is not so high, but, if will happen, a $10+ billion mission will go in the trash can! ...so, why risk???
Also, if this kind of problem will happen while or after a (lunar or earth driven) remote-controlled maneuver, with the (uncrewed) Orion that runs in lunar orbit, the astronauts will have (only) a dead-Orion in orbit, so, they must remain on the moon waiting for a rescue (if they will have sufficient life support) or...
To avoid these (not high, but possible) risks, I suggest to adopt three design changes to the Orion:
1. use a 50-100% redundant solar panels' surface (in other words, up to twice the planned surface).
2. split the total solar panels surface in two parts, half around the Service Module case (a very reliable position) and half in a multi-panels module.
3. adopt an eight-petals "daisy" shaped solar panels instead of the current two-wings "butterfly" shape.
Of course, it's better (for safety) to add (also) many (redundant) rechargeable batteries and split them between the capsule and the Service Module, with a capsule's batteries autonomy of (at least) five days, to give more chances to survive to the astronauts if something goes wrong to the main (SM) solar panels/batteries!
However, the BEST solution to have (both) MORE SAFETY and MORE HABITABLE SPACE, with a (nearly) ZERO ApolloXIII-contingency risk (in, both, the earth-moon and moon-earth travels!!!) is my Soyuz-like Orion's design (suggested in this article) with its THREE MODULES (Command Module Service Module and Habitat Module) ALL with their own (independent) batteries and (TWO) with their own solar panels!The advantage of my (daisy shape + side panels + extra redundancy) design is that, also with a few failed or damaged "petals", the full system still works safely and the $10 billion moon mission doesn't need to abort!
An excellent comment by Craig Fink posted on my groups.google.sci.space.policy thread: "Nice paper. Looks like Orion violates NASA redundancy policy on the Shuttle. It's not fail operational, fail safe. First failure, half the power to the Capsule is gone. Second failure, the other half is gone. And it can occur half way across the Solar System."
May 10 - 2007
To-day's (thin, light, efficient and reliable) solar panels allows to design the solar panel arrays with the shape/size we want/need without increase so much the spacecraft's weight.
After evaluating different shapes (like the early "Soyuz-like" cev panels, the current Orion's "Butterflies" design and my "Daisy" shaped option) I think that the BEST (and most reliable) panels are the "Sails" shaped arrays.
The new solar panels design has FOUR ( independent) "Sails" with two-three independent solar modules each and (just) four independent gimbals that are VERY SIMPLE and RELIABLE since they must only TURN right and left.
Of course, a reliable solar energy source must have a 50-100% active-surface redundancy, so, also if two-three modules will fail (or a full panel goes "out of service") the ($10Bn) Moon mission could be accomplished safely!
Last, the mechanics of the "Sails" solar array is very simple and reliable since it has four (simpler) turn-only gimbals and four (simpler) hinges just EIGHT mechanical systems vs. the 26 (more complex and never tested before) systems of the Orion's "butterflies", also, in my design the gimbals of the four sails are joined to the Service Module in the direction of the sun rather than the direction of the travel (like, both, the Butterfly and the Daisy) then, the gimbals and the panels, NEVER can be damaged when the Orion will be accelerated (at TLI and TEI) or braked (for LOI) the latter by LSAM engines.
May 16 - 2007
The Apollo CSM was built with radiators but it rotates slowly (to avoid an excess of temperature) then, also the Orion (that has radiators) can't fly without rotate, so, I've designed my Sails panels for a rotating vehicle.
A non-rotating vehicle is not a problem in earth and lunar orbits (where the Orion will change its inclination towards the sun almost every minute!) but could be a SERIOUS problem in the (over 3 days each) earth-moon and moon-earth travels with a difference of 300+ °C between the hottest and coldest sides of the Orion/SM/LSAM.
However, I doubt that the Orion and the LSAM (that has big cryogenic tanks and no radiators) can (really) fly over three days without suffer of some dangerous structures' deformations and damages!
A possible alternative to a continuous (slow) rotation, could be a frequent change of the Orion+LSAM side exposed to the sun, but these (computer-driven) operations (over 80 times in 3+ days, assuming ONE change per hour) need an excessive use of the Orion's RCS (that may finish the propellent they use for other, most important, maneuverings!) and could put the crews under a (VERY RISKY) Gemini8-like contingency!!!
Then, since I think that (also) the Orion/LSAM convoy will rotate slowly in the earth-moon-earth travels (that is the simplest and safest solution!) I've designed a second version of my "Sails" shaped solar panels for a rotating Orion.
The new version has four (single or multi-module) large panels made with active cells on both sides (each mounted with 90 degrees of inclination) joined to the SM with a single (z-axis rotation) gimbal each, then having just FOUR (then, very reliable!) mechanical systems in total!!!
About the (current) Orion's "butterfly" design, to-day I've seen a NASA drawing of the Orion's SM rear that shows the dimensions of the rigid modules joined to the gimbals.
Well, its not 1/10th but 1/20th the wing's circumference! In other words, each wing has 20 hinges (not ten!) half of them on the front side of the wing (visible in the Orion image published here) and the second half in the (hidden) rear side!
Then, the two wings of the Orion's "butterfly" have a total of 40 segments/slices and 40 hinges + six other moving-parts (the wing's locking systems and two x/z-axis gimbals) that (ALL) may FAIL, killing a $10Bn moon mission since just ONE defective hinge could HINDE the entire wing to deploy properly!
May 18 - 2007
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Copyright © 2007 Gaetano Marano - All rights reserved - base images used for the drawings are © NASA