Author Topic: “Plan D for Outer Space” - NASA updates EM-2 mission baseline  (Read 11419 times)


Offline Comga

  • Senior Member
  • *****
  • Posts: 4603
  • Liked: 1842
  • Likes Given: 1544
Are they intentionally cutting the reference to three previous plans to avoid this being Plan 9 From Outer Space or was this worded purposely to make that connection?

And everything is still done in nautical miles. (1450 nmi ~2850 km)
Isn’t that first apogee well into the lower Van Allen radiation belt?
« Last Edit: 12/15/2018 01:28 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline david-moon

  • Member
  • Member
  • Posts: 13
  • Liked: 4
  • Likes Given: 0
It is insane to fly a different profile in the uncrewed EM-1 test mission than will be flown in the EM-2 mission.  I hope astronauts don't die due to lack of testing the specific flight profile.
« Last Edit: 12/14/2018 08:42 pm by david-moon »

Offline rpapo

It is insane to fly a different profile in the uncrewed EM-1 test mission than will be flown in the EM-2 mission.  I hope astronauts don't die due to lack of testing the specific flight profile.
Though I agree with you, a young and impetuous NASA did exactly that once upon a time.  The mission was called Apollo 8.
An Apollo fanboy . . . fifty years ago.

Offline david-moon

  • Member
  • Member
  • Posts: 13
  • Liked: 4
  • Likes Given: 0
I don't think Apollo CSM was flyable uncrewed.  Someone had to change the current program in the AGC.

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 9415
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 3250
  • Likes Given: 9145
Thanks for great update Philip and renders Nathan! I just hope we actually get to go someplace before they run out of letters of the alphabet... ???
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Offline John Santos

  • Member
  • Posts: 88
  • Liked: 39
  • Likes Given: 22
I don't think Apollo CSM was flyable uncrewed.  Someone had to change the current program in the AGC.
Of course it was.  There were several unmanned flights before the planned Apollo 1, and  the first 2 Saturn 5 flights (Apollo 4 and 6) included an uncrewed Apollo CSM.

Flying a different trajectory is only a minor difference.  Every flight has a different trajectory, even "routine" Soyuz crew flights to the ISS are each somewhat different than any previous flight.

The details of the specific trajectory and new equipment not previously tested on EM-1 are the big issues to my mind.  The previous plan spent more time in LEO (3 orbits, according to the article), and it says the quick return from the 42 hour orbit isn't much slower than the previous 24 hour orbit (but how much slower?)  I think the previous plan had two 24 hour orbits before departing for the Moon, but I could be wrong about that.  Either allows about 2 days of soak-testing the spacecraft before committing to the Moon.

One 42 hour orbit means only 3 traversals of the Van Allen Belts during the out-bound phase of the mission.  (Once out, once back in and a second time out after TLI.)  Two 24 hour orbits would mean 5 traversals.  Apogee of the 42 hour orbit is well above the outer Van Allen Belt, whereas for the 24 hour orbit, I think it is within or only slightly above the belt.  (This depends on the orbital inclination, though.)  A highly eliptical orbit spends most of its time near apogee, so I suspect there will be significantly less radiation exposure using the new plan.  (Unless there are large solar flares or a CME, but that is independent of trajectory.)

One thing that worries me is the ECS, which would only have about 2 days of testing before departing for the Moon.  I vaguely remember plans to test some or all of it on the ISS.  I think it won't be ready for EM-1, which would fly without a complete or fully functional ECS, and in any case wouldn't have 4 humans consuming oxygen and emitting CO2, water and heat for 2 weeks.

Offline freddo411

  • Full Member
  • *
  • Posts: 188
  • Liked: 169
  • Likes Given: 578

...
One 42 hour orbit means only 3 traversals of the Van Allen Belts during the out-bound phase of the mission. 

Flying a HEO loop stands out to me as a pointless stunt.   Might as well just do your TLI, or stay in LEO, going 1/2 way and coming back is not useful.

...

One thing that worries me is the ECS, which would only have about 2 days of testing before departing for the Moon.  I vaguely remember plans to test some or all of it on the ISS.  I think it won't be ready for EM-1, which would fly without a complete or fully functional ECS, and in any case wouldn't have 4 humans consuming oxygen and emitting CO2, water and heat for 2 weeks.

This is a poor program decision.   It shouldn't be hard to build ECS at this point.   It's unfathomable why this isn't done and built for EM-1.

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8680
  • South coast of England
  • Liked: 403
  • Likes Given: 181
Many of the functions of the Orion's ECLSS can be tested on the Earth by locking people into a capsule on the ground for 2 weeks. Give then some books to read. Running the ECLSS in space in an empty capsule will show that nothing falls off during launch or re-entry.

Offline TaurusLittrow

  • Full Member
  • *
  • Posts: 108
  • Pennsylvania, USA
  • Liked: 76
  • Likes Given: 36
It is insane to fly a different profile in the uncrewed EM-1 test mission than will be flown in the EM-2 mission.  I hope astronauts don't die due to lack of testing the specific flight profile.
Though I agree with you, a young and impetuous NASA did exactly that once upon a time.  The mission was called Apollo 8.

I devoutly wish EM-2 could fly the Apollo 8 mission profile, but the selection of lunar orbits is constrained by the capability of the combined SLS and Orion system.

Access (orbit insertion plus return) to simple “Keplerian” orbits—such as low-lunar orbits, prograde circular orbits, and elliptical lunar orbits—is simply infeasible or only marginally achievable with the SLS/Orion system.

These orbits are essentially off the table since access from Earth is restricted by SLS’s performance margin and Orion/ESM’s limited propellant load.

That's why EM-2 is a circumlunar mission instead of a lunar orbital one like Apollo 8.

Offline woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 9036
  • IRAS fan
  • The Netherlands
  • Liked: 6365
  • Likes Given: 2194
I don't think Apollo CSM was flyable uncrewed.  Someone had to change the current program in the AGC.
Of course it was.  There were several unmanned flights before the planned Apollo 1, and  the first 2 Saturn 5 flights (Apollo 4 and 6) included an uncrewed Apollo CSM.

This.

It is astounding to see just how little some of the folks here seem to know about the older programs. The ignorami here would do themselves a huge service by reading up on spaceflight history first before making posts that only serve to embaress themselves.

Every single spacecraft in US history (with the exception of the space shuttle) first flew, or will fly, one-or-more unmanned missions: Mercury, Gemini, Apollo, Orion, Starliner, Crew Dragon.

The Soviets (now Russia) did exactly the same. All of their manned vehicles (or intented to be manned vehicles) first flew one-or-more unmanned missions: Vostok, Voskhod, Soyuz, Zond, Buran.
« Last Edit: 12/17/2018 11:29 am by woods170 »

Offline Zed_Noir

  • Senior Member
  • *****
  • Posts: 2726
  • Canada
  • Liked: 466
  • Likes Given: 692
Many of the functions of the Orion's ECLSS can be tested on the Earth by locking people into a capsule on the ground for 2 weeks. Give then some books to read. Running the ECLSS in space in an empty capsule will show that nothing falls off during launch or re-entry.

There is the small matter of micro gravity and how does one simulated it on Earth for the dirtside ECLSS test results to be valid.  ::)

Online niwax

  • Full Member
  • ****
  • Posts: 409
  • Germany
    • SpaceX Booster List
  • Liked: 278
  • Likes Given: 59
It is insane to fly a different profile in the uncrewed EM-1 test mission than will be flown in the EM-2 mission.  I hope astronauts don't die due to lack of testing the specific flight profile.
Though I agree with you, a young and impetuous NASA did exactly that once upon a time.  The mission was called Apollo 8.

I devoutly wish EM-2 could fly the Apollo 8 mission profile, but the selection of lunar orbits is constrained by the capability of the combined SLS and Orion system.

Access (orbit insertion plus return) to simple “Keplerian” orbits—such as low-lunar orbits, prograde circular orbits, and elliptical lunar orbits—is simply infeasible or only marginally achievable with the SLS/Orion system.

These orbits are essentially off the table since access from Earth is restricted by SLS’s performance margin and Orion/ESM’s limited propellant load.

That's why EM-2 is a circumlunar mission instead of a lunar orbital one like Apollo 8.

Which puts into question what EM-1 and EM-2 are about at all. They're testing a system that will not be able to actually perform a useful mission. Early Apollo at least was in preparation for a landing.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8680
  • South coast of England
  • Liked: 403
  • Likes Given: 181
Many of the functions of the Orion's ECLSS can be tested on the Earth by locking people into a capsule on the ground for 2 weeks. Give then some books to read. Running the ECLSS in space in an empty capsule will show that nothing falls off during launch or re-entry.

There is the small matter of micro gravity and how does one simulated it on Earth for the dirtside ECLSS test results to be valid.  ::)

You do not simulate micro gravity dirtside (other than by turning the equipment on its side). Flight testing the effects of micro gravity is an additional reason for the ECLSS to be switched on during EM-1. Ground test, unmanned flight test and manned flight test of Orion's ECLSS.

Offline zodiacchris

  • Full Member
  • *
  • Posts: 192
  • Port Macquarie, Australia
  • Liked: 363
  • Likes Given: 405
But that’s the point, no ECLSS on EM1, it won’t be ready in time. Turning it upside down or sideways on earth is not a valid simulation for microgravity either...
Whatever happened to ‘test like you fly’?
« Last Edit: 12/17/2018 12:59 am by zodiacchris »

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 4897
  • California
  • Liked: 4708
  • Likes Given: 2827
But that’s the point, no ECLSS on EM1, it won’t be ready in time. Turning it upside down or sideways on earth is not a valid simulation for microgravity either...
Whatever happened to ‘test like you fly’?

It is difficult and very time consuming to test as you fly when you have an anemic flight rate of one flight per 18-24 months.

Normally one would suggest another EFT flight on a Delta IV-H, but that’s also difficult if your backup launcher is also incredibly expensive and not mandated. Orion really could have used a Saturn I to its Saturn V (SLS) for LEO testing.

Although if Orion development is just as long pole as SLS (?) then the benefit of that is questionable. Such a mess.
« Last Edit: 12/17/2018 02:00 am by Lars-J »

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8680
  • South coast of England
  • Liked: 403
  • Likes Given: 181
But that’s the point, no ECLSS on EM1, it won’t be ready in time. Turning it upside down or sideways on earth is not a valid simulation for microgravity either...
Whatever happened to ‘test like you fly’?

Turning a piece of equipment upside down may not be a valid simulation of micro-gravity but it is not invalid since anything that will float apart will fall apart. It also verifies that fluids are pumped rather than gravity fed.

To flight test the ECLSS either delaying EM-1 or adding an extra unmanned flight may be advisable.

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8680
  • South coast of England
  • Liked: 403
  • Likes Given: 181
But that’s the point, no ECLSS on EM1, it won’t be ready in time. Turning it upside down or sideways on earth is not a valid simulation for microgravity either...
Whatever happened to ‘test like you fly’?

It is difficult and very time consuming to test as you fly when you have an anemic flight rate of one flight per 18-24 months.

Normally one would suggest another EFT flight on a Delta IV-H, but that’s also difficult if your backup launcher is also incredibly expensive and not mandated. Orion really could have used a Saturn I to its Saturn V (SLS) for LEO testing.

Although if Orion development is just as long pole as SLS (?) then the benefit of that is questionable. Such a mess.

The Falcon Heavy may not be able to get the Orion spacecraft to the Moon but it can put a 26 tonne object in LEO.

We can all see the political problems.

Offline woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 9036
  • IRAS fan
  • The Netherlands
  • Liked: 6365
  • Likes Given: 2194
But that’s the point, no ECLSS on EM1, it won’t be ready in time. Turning it upside down or sideways on earth is not a valid simulation for microgravity either...
Whatever happened to ‘test like you fly’?

There is only a partial ECLSS on EM-1, specifically a rudimentary ECS.
The "Life Support" portion is still in development. Besides, even if a full-blown ECLSS was on EM-1 it could not be properly tested.
You see, there is nobody on board to breathe.

Breathing does four things for an ECLSS:
- Use up oxygen (which must be replenished by the ECLSS)
- Produce CO2 (which must be scrubbed by the ECLSS)
- Produce water vapour (which must be largely removed by the ECLSS)
- Produce particle effluent (which must be largely filtered by the ECLSS)

Other than the little detail of breathing, humans also shed a lot of other stuff into the atmosphere, mainly hairs and dead skin tissue (skin flaking). Both must be filtered from the cabin environment. That, again, is done by the ECLSS.

Simply put: testing an ECLSS on board an unmanned spacecraft is like testing the driving experience of a car without the car rolling so much as an inch: it is pointless.

Hence all the crap the ASAP was making about the original flight profile of EM-2. The first manned flight of Orion, with a brand-new, not-flight-tested ECLSS. And it was to go straight to the Moon. The compromise they have now come up with is not committing to TLI until more than 24 hours after launch. If the ECLSS throws a fit the crew will simply not perform the TLI burn and reenter as soon as possible.
« Last Edit: 12/17/2018 09:21 am by woods170 »

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8680
  • South coast of England
  • Liked: 403
  • Likes Given: 181
{snip}
Simply put: testing an ECLSS on board an unmanned spacecraft is like testing the driving experience of a car without the car rolling so much as an inch: it is pointless.

Hence all the crap the ASAP was making about the original flight profile of EM-2. The first manned flight of Orion, with a brand-new, not-flight-tested ECLSS. And it was to go straight to the Moon. The compromise they have now come up with is not committing to TLI until more than 24 hours after launch. If the ECLSS throws a fit the crew will simply not perform the TLI burn and reenter as soon as possible.

That is why the test sequence I gave in reply #8 starts with people locked up in an Orion for 2 weeks. All the parts of the ECLSS have to work, if something fails then it is easy to get them out. The second part of the test ensures that flying the ECLSS does not cause any problems without risking any lives. Even empty temperature controls and fans still have to work. The third part tests Orion and ECLSS with people inside.

Tags: