Author Topic: DARPA Experimental Spaceplane 1 (XS-1) Program  (Read 282276 times)

Offline envy887

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #820 on: 07/24/2018 05:39 pm »
Quote
After deploying the upper stage, the booster is an unpowered glider. For lower speed deployments, it will flyback to a landing field at the launch site; for higher speed deployments that take it beyond range of a return to the launch site, it can land on runways downrange.
So I guess it's mostly going to be gliding to downrange sites. I'm not sure what kind of launch would allow it to glide back to the launch site.

I'm not sure what launch sites and azimuths would allow it to land downrange. This needs a runway, not a barge. There aren't many runways downrange from existing launch sites.

Offline Prettz

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #821 on: 07/24/2018 07:28 pm »
I'm probably just misunderstanding this thing's operations. I was imagining it launching on space shuttle like trajectories so it could glide back to land somewhere up the coast.

Is the idea that it's going to be launching on more lofted trajectories so it's never very far downrange at separation?

Offline envy887

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #822 on: 07/25/2018 01:44 am »
I'm probably just misunderstanding this thing's operations. I was imagining it launching on space shuttle like trajectories so it could glide back to land somewhere up the coast.

Is the idea that it's going to be launching on more lofted trajectories so it's never very far downrange at separation?

I'm not sure, but I imagine a depressed trajectory is also an option as long as the upper stage has a good amount of thrust. Keeping the booster apogee low will reduce the time before reentry, which limits the downrange distance and makes it easier to glide back.

Online ncb1397

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #823 on: 07/25/2018 01:48 am »
Why not do a boost back maneuver?

Offline ZachS09

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #824 on: 07/25/2018 01:51 am »
Why not do a boost back maneuver?

Probably because the AR-22 is not restartable.
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Online ncb1397

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #825 on: 07/25/2018 01:54 am »
Why not do a boost back maneuver?

Probably because the AR-22 is not restartable.

Why do you have to cut the engine off?

Shuttle RTLS:

Quote
Return to launch site (RTLS) was the first abort mode available and could be selected just after SRB jettison. The Shuttle would continue downrange to burn excess propellant, as well as pitch up to maintain vertical speed in aborts with an SSME failure. After burning sufficient propellant, the vehicle would be pitched all the way around and begin thrusting back towards the launch site
https://en.wikipedia.org/wiki/Space_Shuttle_abort_modes
« Last Edit: 07/25/2018 01:58 am by ncb1397 »

Offline ZachS09

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #826 on: 07/25/2018 01:58 am »
Why not do a boost back maneuver?

Probably because the AR-22 is not restartable.

Why do you have to cut the engine off?

Well, the engine can be reused for future flights, but once its single burn is completed, it's not ignited during the glideback to landing.
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Online QuantumG

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #827 on: 07/25/2018 02:00 am »
Why do you have to cut the engine off?

Shuttle RTLS:
<snip>

Right, so you're gunna do staging with the SSME running?


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Online ncb1397

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #828 on: 07/25/2018 02:03 am »
Why do you have to cut the engine off?

Shuttle RTLS:
<snip>

Right, so you're gunna do staging with the SSME running?

Shuttle boosters staged with the SSMEs running. This is side mount, not top mount.

Online QuantumG

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #829 on: 07/25/2018 02:06 am »
Shuttle boosters staged with the SSMEs running. This is side mount, not top mount.

Fair 'nuff.
Human spaceflight is basically just LARPing now.

Offline RDoc

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #830 on: 07/25/2018 08:15 pm »
Based on the picture, aren't they going to have falling ice and/or insulation issues with the second stage?

Those wings and winglets also look pretty big for anything like Mach 10 to me, but I'm no expert.

Offline envy887

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #831 on: 07/25/2018 08:30 pm »
Why do you have to cut the engine off?

Shuttle RTLS:
<snip>

Right, so you're gunna do staging with the SSME running?

Shuttle boosters staged with the SSMEs running. This is side mount, not top mount.

The SRBs were not running, they were essentially burnt out which reduces the risk of recontacting. And more importantly, nobody cared if the SSMEs smoked them on the way past.

Boeing's promo video shows MECO followed by staging in freefall:

Online Elmar Moelzer

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #832 on: 11/15/2018 01:54 pm »
Fabrication of composite cryotanks in progress. Really feels like this project is moving at a snails pace, doesn't it? Well at least it ain't dead yet.
https://www.boeing.com/features/2018/11/phantom-express-tank-fabrication-11-18.page

Also looks like the general page for Phantom Express has been updated with more details and info (at least  have not seen it yet):
https://www.boeing.com/space/phantom-express/index.page#/capabilities
« Last Edit: 11/15/2018 01:56 pm by Elmar Moelzer »

Offline Rocket Science

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #833 on: 11/15/2018 02:44 pm »
Fabrication of composite cryotanks in progress. Really feels like this project is moving at a snails pace, doesn't it? Well at least it ain't dead yet.
https://www.boeing.com/features/2018/11/phantom-express-tank-fabrication-11-18.page

Also looks like the general page for Phantom Express has been updated with more details and info (at least  have not seen it yet):
https://www.boeing.com/space/phantom-express/index.page#/capabilities
Maybe they want to put any cryopumping issues to rest first...
https://www.compositesworld.com/articles/nasaboeing-composite-launch-vehicle-fuel-tank-scores-firsts
« Last Edit: 11/15/2018 02:47 pm by Rocket Science »
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Offline Star One

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DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #834 on: 11/15/2018 03:18 pm »
Fabrication of composite cryotanks in progress. Really feels like this project is moving at a snails pace, doesn't it? Well at least it ain't dead yet.
https://www.boeing.com/features/2018/11/phantom-express-tank-fabrication-11-18.page

Also looks like the general page for Phantom Express has been updated with more details and info (at least  have not seen it yet):
https://www.boeing.com/space/phantom-express/index.page#/capabilities

Saying this project is moving at a snails pace is something of an unreasonable statement. It has actually moved comparable fast by government project standards.
« Last Edit: 11/15/2018 03:28 pm by Star One »

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #835 on: Today at 06:55 am »
According to this

https://spaceflightnow.com/2018/07/18/rapid-fire-engine-tests-raise-hopes-for-darpas-planned-reusable-spaceplane/

Boeing will conduct a CDR in early 2019, with first test flight (without expendable US) in 2021, about 1 year behind schedule.

It could be argued that 1 year is not a bad schedule slip for a relatively radical vehicle.

If they are serious on saving recurring costs for this a key question would be how far can they simplify the expendable US?

Could the booster have such precise orbital parameters that even the worst case dispersion parameters of the US (I'm assuming it's a solid) still put the payload in the right orbit?

Failing that could they avoid needing a full US INS? The 3 key parameters are altitude, burnout velocity and inclination. The boosters INS should have the US in  a fairly small patch of the sky to begin with (it would be very poor if it didn't).

The other big ticket item would be TVC on the US. Eliminating this saves serious money, not just the mechanical complexity in the nozzle(s) and , also the power needed to run it.
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Online daedalus1

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #836 on: Today at 07:12 am »
John Smith just a minor point, when you use abbreviations could you write them in full on first use please.
Thanks

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