Poll Which NASA plan does the Orbiter community prefer?

[Ark]

Landing on the surface of an NEO isn't that hard. It's like docking with moondust.

They managed to land an extremely delicate probe on one without destroying it, so it can't be that hard.

---------- Post added at 04:08 PM ---------- Previous post was at 04:07 PM ----------

I'm with you Donamy. I never understood why the Side-Mount was never thought of as the best option. DIRECT is good but a side mount Orion would be much better at presurving the workforce, and eliminating the gap.

Sidemount has the same crew safety issues as the Shuttle did, there's virtually no chance of survival if something goes wrong. Which is why I'd support Sidemount as a heavy-lift cargo launcher.

 

[Donamy]

They managed to land an extremely delicate probe on one without destroying it, so it can't be that hard.

---------- Post added at 04:08 PM ---------- Previous post was at 04:07 PM ----------



Sidemount has the same crew safety issues as the Shuttle did, there's virtually no chance of survival if something goes wrong. Which is why I'd support Sidemount as a heavy-lift cargo launcher.

Wrong, it would have the escape system.

 

[Andy44]

Sidemount has the same crew safety issues as the Shuttle did, there's virtually no chance of survival if something goes wrong. Which is why I'd support Sidemount as a heavy-lift cargo launcher.

There's no reason a launch escape system couldn't be implemented for Sidemount. It avoids the two biggest problems that killed two shutle crews: wing leading edges and no way to eject the crew module from a stricken launch vehicle.

And yeah, it would make a great cargo heavy lifter as well.

Considering that Sidemount's cousin, Shuttle C, had been thought of before, I am puzzled as to why they didn't give this one more consideration, since it was clear that they were trying to re-use shuttle hardware, facilities, and ground crews. I guess this wasn't the right person's pet project.

 

[garyw]

Sidemount would work farily well if you effectively stuck a service module, a command module and a protection sheild on the module for launch.
This way, you have protection for the command module and the heat shield.
You lose cargo capability for the crew version but you can get around that with two launches, i.e. Shuttle-C for cargo which arrives and "parks" at the ISS then sidemount with an Apollo-esque capsule.

The SSME's would need to be replaced with throwaway engines. I think RD-180's(?) were considered at one point?

 

[Linguofreak]

It avoids the two biggest problems that killed two shutle crews: wing leading edges and no way to eject the crew module from a stricken launch vehicle.

To a great degree, yes. Columbia certainly wouldn't have happened with Sidemount, and there's a good chance the Challenger crew would have made it, but I still think there's a better chance with Sidemount than with a pure tower of the capsule ending up colliding with debris during a breakup.

 

[zerofay32]

You lose cargo capability for the crew version...

No, you can still get a good amount of cargo on an ISS mission profile. Around 80 mt if I remember correctly.

 

[anemazoso]

And yeah, it would make a great cargo heavy lifter as well.

Considering that Sidemount's cousin, Shuttle C, had been thought of before, I am puzzled as to why they didn't give this one more consideration, since it was clear that they were trying to re-use shuttle hardware, facilities, and ground crews. I guess this wasn't the right person's pet project.

I think the main reason they didn't go with the sidemount is that they wanted as big of a booster as was reasonable. As you'll remember Ares V started out with the 4 segment and 4-5 SSMEs and it just grew bigger and bigger. Which I think created a chain of decisions that were ultimately the demise of the program. When they decided to go with the 5 segment and the J-2X instead of modifying an SSME for vacuum lite for Ares I in order to develop parts for the EDS and ARES V sooner it brought more of the cost of the whole Constellation program sooner. Looking back (a little Tuesday morning QBing here) I think if NASA would have went with the cheapest and quickest way initially to a Crew Launch Vehicle whatever that would have been we wouldn't be in this situation. There could have been a lot smaller gap, it could have been within budget and it wouldn't have been so heavily scrutinized, all of which caused the formation of the Augustine Commission and any questioning of the Constellation as a whole.

What would've been ideal in my opinion is the sidemount from the beginning. With that as the only vehicle used along with Orion built as a straight bid contract instead of cost plus. Still have ever increasing prizes to coax privet industry into being while slowly privatizing some of the more mundane aspects of the operation like LEO. That and the extra $6.8 billion Obama has proposed for use in tech research such as on orbit refuel, ISRU, in space propulsion for use on a tug and maintaining the ISS until atleast 2020 when they could sell it to a private interest for use as a hotel or a for-lease lab like MIR almost was. With an international effort on a lunar lander and surface hab modules we could have set up camp on the moon in the original intended time frame of 2020-2022 and help to develop a private human space travel sector.

But given these two choices of an underfunded Constellation or Obama's plan I would go with the latter.

---------- Post added at 03:06 PM ---------- Previous post was at 03:04 PM ----------

The SSME's would need to be replaced with throwaway engines. I think RD-180's(?) were considered at one point?

I think it was the RS-68 because it is just an updated simplified version of an SSME with heat ablation instead of intrinsic cooling.

 

[Ark]

In the event of a Challenger repeat, I don't see how a Sidemount launch escape system would get the crew away in time. Putting the capsule at the top of the rocket means that any explosion or combustion would happen below the crew, maximizing their chance of getting safely away from an emergency.

Until bits of flaming SRB fuel melt the parachutes, of course.

 

[Andy44]

In the event of a Challenger repeat, I don't see how a Sidemount launch escape system would get the crew away in time. Putting the capsule at the top of the rocket means that any explosion or combustion would happen below the crew, maximizing their chance of getting safely away from an emergency.

Until bits of flaming SRB fuel melt the parachutes, of course.

Challenger's crew did get away in time, alive. They just didn't have the proper equipment to survive the ensuing fall. And they weren't even in a capsule made for that kind of abuse.

The fact is that any time a launch vehicle breaks up or explodes, survival becomes dicey. But since Challenger's post-accident SRB redesign, the shuttle stack has been very well-behaved and reliable, except for debris shedding, which ceases to be a problem when your spacecraft no longer has fragile RCC leading edges.

Sidemount has risks, of course, but much less than STS, and it brings a lot of benefits. (In theory, anyway).

ETA: The Challenger accident would've been predictable if more sensors were placed at various places on the stack, which is easier with current technology. The problem started at liftoff, so if this were to happen on Sidemount the capsule would have 73 seconds to make the decision to abort.

What I'm trying to say is that when you have an LES and a good sensor suite, the shuttle stack suddenly becomes more survivable in certain situations.

 

[Hielor]

Challenger's crew did get away in time, alive. They just didn't have the proper equipment to survive the ensuing fall. And they weren't even in a capsule made for that kind of abuse.

I would argue that if you don't survive an event, you didn't "get away in time."

 

[JamesG]

Penny wise, pound foolish.
If they had taken the time to build the EFTs to be carried to orbit to be stacked up as mass and pressurised space (or those orbital fuel depots they are now talking about) they would not have been vulnerable to what destroyed Columbia and might have prevented Challenger.

Beyond the loss of two Orbiters, all that mass is now laying on the bottom of the Indian Ocean...

 

[Andy44]

I would argue that if you don't survive an event, you didn't "get away in time."

Then you're not paying attention to the discussion. They survived the breakup, which was the event in question.

 

[Ark]

Safety issues aside, the Sidemount concept preserves a lot of the Shuttle infrastructure and jobs. Which, frankly, means it'll preserve almost all of the Shuttle's vastly inflated cost of operation. And that's not progress. Kinda sucks, but that empire of people required for every Shuttle launch is a huge impediment to the lowering of spaceflight costs.

 

[chameleon]

I remembered that reminded me of the Obama plan. History since the collapse of the Soviet Union.
Ares - as Еnergy. The lunar program associated with heavy missile. The subsequent rejection of them and keeping only space station program.

 

[Andy44]

I remembered that reminded me of the Obama plan. History since the collapse of the Soviet Union.
Ares - as Еnergy. The lunar program associated with heavy missile. The subsequent rejection of them and keeping only space station program.

Lots of people seem disappointed over this, but I think you have to put this in historical context. Big government space programs are kind of a fluke, and they stem from the fiscally disastrous Cold War, which ran the Soviet government out of business and is still costing the US.

With no Cold War goal for NASA, the writing was on the wall. That the shuttle lasted for so long is remarkable, given its failure to recoup its costs. Buran wasn't so lucky.

Americans and space fans around the world take it for granted that space travel will always be the purview of giant government agencies, but it doesn't have to be that way.

 

[zerofay32]

Safety issues aside, the Sidemount concept preserves a lot of the Shuttle infrastructure and jobs. Which, frankly, means it'll preserve almost all of the Shuttle's vastly inflated cost of operation. And that's not progress. Kinda sucks, but that empire of people required for every Shuttle launch is a huge impediment to the lowering of spaceflight costs.

With side mounts you eliminate the most expensive part of the STS stack, the Orbiter. A lot of the operation cost is to get the orbiter ready again. It is the main factor in the overall cost for vehicle turnaround. For launch operations cost, you replace the orbiter's systems with the reletively simple Orion and payload carrier systems. Remove systems and reduce the complexity of the vehicle, you need less people to monitor the launch thus reducing overall cost. And you could, in theory, have more systems monitored by computers.

 

[Urwumpe]

Challenger's crew did get away in time, alive. They just didn't have the proper equipment to survive the ensuing fall. And they weren't even in a capsule made for that kind of abuse.

And it is likely that flying around debris also injured them, since even the panels would have problems staying screwed on at 22g.

But it would have been better Challenger did not launch at all, since the danger was known.

The biggest problem for the shuttle is actually, that it does not have thrusters powerful enough to separate the Shuttle from the half-full tank safely and accelerate it to a good gliding speed. It is always nearly impossible to get all phases of ascent covered, but the Shuttle is on the more extreme end with over two minutes without abort chance.

And never ignore the fact that the crew escape systems for capsules often weight as much as the capsule themselves.

 

[Andy44]

And never ignore the fact that the crew escape systems for capsules often weight as much as the capsule themselves.

True, but a Sidemount manned mission has lots of of extra payload mass to spare, some of that can be traded for LES.

Certainly beats Ares I, which required the capsule itself to be stripped down to bare bones before it could make orbit.

Even if NASA starts buying rides on Dragon-Falcon or some other vehicle, some day they're going to need a heavier lift cargo vehicle, a privatized Sidemount-style vehicle may be a better option than a Saturn clone. I realize this will never happen, as the tooling will be gone by the time NASA ever gets back to launching heavies.

 

[anemazoso]

Even if NASA starts buying rides on Dragon-Falcon or some other vehicle, some day they're going to need a heavier lift cargo vehicle, a privatized Sidemount-style vehicle may be a better option than a Saturn clone. I realize this will never happen, as the tooling will be gone by the time NASA ever gets back to launching heavies.

I think the biggest rocket they will buy from industry is an EELV heavy and I seriously think they don't need anything bigger anyway.

 

[Andy44]

Everybody keeps saying that they "don't need anything heavy", but I don't get it.

You want to explore space? Really explore it? Then you need something heavy. All this business of manufacturing large complex structures in a zero-G vaccuum is fantasy. The only thing we know how to build in space is stuff we can pre-fab on the geound and clamp together in orbit, which means no large-volume structures.