Masten Space Systems Update

[robertross]

FWIW,

Here's a movie from the day before our Level 2 attempts.  We needed to make sure Xoie could fly a full 180s with the challenge payload, so we setup to do a depletion burn.  The weather was awful, gusting well over 30 knots IIRC, but it was just within our waiver limits, and we needed the data.  I'm not positive, but I think that if you count tether testing, this was the longest flight ever of a VTVL rocket.

Hopefully, we should have some other news sometime soon.

~Jon

That was super-impressive. Thanks!

I love everyone doing their Monty Python routine to 'run away' before ignition

Did the engine suffer any negative effects from such a long duration burn? It seemed to handle itself extremely well. Bravo.

[jongoff]

FWIW,

Here's a movie from the day before our Level 2 attempts.  We needed to make sure Xoie could fly a full 180s with the challenge payload, so we setup to do a depletion burn.  The weather was awful, gusting well over 30 knots IIRC, but it was just within our waiver limits, and we needed the data.  I'm not positive, but I think that if you count tether testing, this was the longest flight ever of a VTVL rocket.

Hopefully, we should have some other news sometime soon.

~Jon

That was super-impressive. Thanks!

I love everyone doing their Monty Python routine to 'run away' before ignition

Did the engine suffer any negative effects from such a long duration burn? It seemed to handle itself extremely well. Bravo.

Nope.  We put another 9 minutes of flight time on it over the rest of that week (our first Level two attempt, where the vehicle caught fire shortly after landing, and then our two prize-winning back-to-back 3-minute flights).  I think that by the time Xoie touched down after the Level-Two winning flight, it had 20-25 minutes of hover time over about a dozen flights.  We disassembled the engine after the flights, and in spite of having an aluminum chamber it was pristine--no thermal warping or discoloration.  In fact it just slid out of the jacket as though it had never been fired.  There's still a few improvements we want to put into the engine (going to BLDCs for the electric actuators, making sure our igniter setup is capable of reliable in-air relights, etc), but it was really pleasing to see our hard work over the past year really pay off.  The first time we fired our first rev of the 750-class engines was a year ago next week.

~Jon

[jongoff]

6km/s is border line LEO to Moon's surface and LEO to Phobos.  There may be a market landing say spare parts.

Well, to be fair an actual LEO to Lunar Surface or LEO to Phobos system would require a lot of extra capabilities we don't have (yet).  Teamed up with the right group (a smallsat company or a more traditional aerospace company), I think we could do really interesting things, but it'll be a while on our own before we're actually capable of doing anything quite that fancy.

~Jon

[kkattula]

6 km/s, in an upper stage, combined with a little over 3 km/s 'sub-orbital' lower stage, is enough for Earth to LEO.

Xoie is what, about 1.9 km/s now?

[Nomadd]

Let's see ...Me, a lawn chair and a surplus Orlon at $250 a kg.....Larry would be proud.

[jongoff]

6 km/s, in an upper stage, combined with a little over 3 km/s 'sub-orbital' lower stage, is enough for Earth to LEO.

Xoie is what, about 1.9 km/s now?

Well, 1.9km/s if you're trying to hover at low altitudes for the whole burn.  Remember that the rocket equation has delta-V as a function of both "mission-averaged" Isp, and mass ratio.

On the mission-averaged Isp side, hovering at low altitude on earth ends-up really killing your mission averaged Isp.  When you decrease the flow of propellants into the chamber, you get hit with two losses.  First, the c* efficiency drops because the propellant mixing is partially driven by injection velocity, and that drops as less flow tries to go through the same size injector holes.  You can fix this with a throttling injector that changes its area, but we didn't go that route for our vehicle.  The other, much bigger loss is that since you have less propellant in the chamber, the chamber pressure is lower, so you have less pressure and temperature available to convert into kinetic energy, and the exhaust pressure drops lower and lower compared to ambient.  Because of all this, we had to make two compromises--first we had to run our tanks at a lot higher pressure than a pressure-fed system usually wants to, since at minimum throttle we still had to have something that wasn't so overexpanded as to run into problems.  The other compromise is we had to go with a much shorter expansion nozzle, for the same reasons.

If you took our existing Xoie vehicle, and had it go full-throttle in vacuum, it would deliver around 2600-2700m/s of delta-V.  If you gave it a more vacuum optimized nozzle, you could get it up into the 3300m/s range. 

Right now, our tanks are pretty overbuilt, because we both need a high chamber pressure due to low-altitude throttling operations, and because we are reusing the tanks hundreds of times.  By lowering the pressure to more typical pressure-fed values (which also happen to be around the minimum gage thickness for the composite tanks), and going with more traditional factors of safety, and with the better T/W ratio we're expecting with a 3k engine, it's quite feasible to pack 3-4x the propellant into a system that weighs about the same as Xoie without going to more advanced fabrication techniques.

Basically...at least in our case, you can actually get a lot more performance out of the system if you use it for an orbital-type mission than it can for low altitude hovering.

~Jon

[jongoff]

Videos later, but we did our first three untethered boosted hops today.  First two were picture perfect, third one was perfect on the way up, but the ground control lost communication with the vehicle right around apogee, so it soft aborted (that means it did an autoland maneuver, not that it dropped out of the sky).  Good to know the aborts brought the vehicle home safely without any damage.  Third flight was our highest to-date: 240ft (just under the limit of our current FAA waiver).

Once we get the new waiver, we should be able to go to 1500ft.

~Jon

[Robotbeat]

Videos later, but we did our first three untethered boosted hops today.  First two were picture perfect, third one was perfect on the way up, but the ground control lost communication with the vehicle right around apogee, so it soft aborted (that means it did an autoland maneuver, not that it dropped out of the sky).  Good to know the aborts brought the vehicle home safely without any damage.  Third flight was our highest to-date: 240ft (just under the limit of our current FAA waiver).

Once we get the new waiver, we should be able to go to 1500ft.

~Jon

Wow, congratulations! It's neat to know your soft aborts work that well.

[jongoff]

Videos later, but we did our first three untethered boosted hops today.  First two were picture perfect, third one was perfect on the way up, but the ground control lost communication with the vehicle right around apogee, so it soft aborted (that means it did an autoland maneuver, not that it dropped out of the sky).  Good to know the aborts brought the vehicle home safely without any damage.  Third flight was our highest to-date: 240ft (just under the limit of our current FAA waiver).

Once we get the new waiver, we should be able to go to 1500ft.

~Jon

Wow, congratulations! It's neat to know your soft aborts work that well.

Well, I generally prefer to test aborts *intentionally* and then never see them again otherwise.  But yeah, intact abort capability is nice.  We'd have gone under as a business long ago if we had to make everything work perfectly the first time and every time.

~Jon

[robertross]

Videos later, but we did our first three untethered boosted hops today.  First two were picture perfect, third one was perfect on the way up, but the ground control lost communication with the vehicle right around apogee, so it soft aborted (that means it did an autoland maneuver, not that it dropped out of the sky).  Good to know the aborts brought the vehicle home safely without any damage.  Third flight was our highest to-date: 240ft (just under the limit of our current FAA waiver).

Once we get the new waiver, we should be able to go to 1500ft.

~Jon

Hey, that's great! I'm glad no hardware was damaged, and you got an additional test out of it.

Thanks for the update!

[jongoff]

Videos later, but we did our first three untethered boosted hops today.  First two were picture perfect, third one was perfect on the way up, but the ground control lost communication with the vehicle right around apogee, so it soft aborted (that means it did an autoland maneuver, not that it dropped out of the sky).  Good to know the aborts brought the vehicle home safely without any damage.  Third flight was our highest to-date: 240ft (just under the limit of our current FAA waiver).

Once we get the new waiver, we should be able to go to 1500ft.

~Jon

Hey, that's great! I'm glad no hardware was damaged, and you got an additional test out of it.

Thanks for the update!

The guys are downloading the videos from the cameras, then getting them ready to put on youtube.  Once they have them up on youtube I'll post a link.

~Jon

[jongoff]

I don't know if they'll get any other ones up before the weekend, but here's a view taken from a camera Ben buried right next to the pad pointing up.



This was our highest flight (to just a few feet below our waiver altitude limit).  If I hadn't mentioned that it soft aborted a couple of seconds into the descent, I don't think any of you would've realized it was an off-nominal flight, huh?

~Jon

[kevin-rf]

That is one awesome video! Is that marshmellows I hear roasting at the end of the flight

[mlorrey]

I don't know if they'll get any other ones up before the weekend, but here's a view taken from a camera Ben buried right next to the pad pointing up.



This was our highest flight (to just a few feet below our waiver altitude limit).  If I hadn't mentioned that it soft aborted a couple of seconds into the descent, I don't think any of you would've realized it was an off-nominal flight, huh?

~Jon

Wow Jon, you should shop that around hollywood....

[kkattula]

6 km/s, in an upper stage, combined with a little over 3 km/s 'sub-orbital' lower stage, is enough for Earth to LEO.

Xoie is what, about 1.9 km/s now?

Well, 1.9km/s if you're trying to hover at low altitudes for the whole burn.  Remember that the rocket equation has delta-V as a function of both "mission-averaged" Isp, and mass ratio.

...

Basically...at least in our case, you can actually get a lot more performance out of the system if you use it for an orbital-type mission than it can for low altitude hovering.

~Jon

That's pretty much what I thought or even better.

I've seen some people dismiss the LLC vehicles as just 'toys for rich men'. They don't appreciate just how much potential performance is implied by achieving level 2.

You guys are doing great work!

[jongoff]

FYI, Ben gave a really cool "ignite talk" at the SpaceUp unconference down in San Diego last week.  Here's a picture from the presentation:

http://www.flickr.com/photos/kevlar/4403551010/

I wasn't able to go, but having seen the presentation it was hilarious and an excellent way of describing our style.  We haven't been able to locate a video yet, but if we can, we'll put it up.

~Jon

[jongoff]

Fun video of Xoie's disassembly back in December:



~Jon

[Nomadd]

 Was that a time lapse, or do you guys have a really large coffee bill?
 I guess it was a lot better than the considerably more rapid, unplanned disassembly I experienced on a missile motor when I was younger.

[William Barton]

6 km/s, in an upper stage, combined with a little over 3 km/s 'sub-orbital' lower stage, is enough for Earth to LEO.

Xoie is what, about 1.9 km/s now?

Well, 1.9km/s if you're trying to hover at low altitudes for the whole burn.  Remember that the rocket equation has delta-V as a function of both "mission-averaged" Isp, and mass ratio.

On the mission-averaged Isp side, hovering at low altitude on earth ends-up really killing your mission averaged Isp.  When you decrease the flow of propellants into the chamber, you get hit with two losses.  First, the c* efficiency drops because the propellant mixing is partially driven by injection velocity, and that drops as less flow tries to go through the same size injector holes.  You can fix this with a throttling injector that changes its area, but we didn't go that route for our vehicle.  The other, much bigger loss is that since you have less propellant in the chamber, the chamber pressure is lower, so you have less pressure and temperature available to convert into kinetic energy, and the exhaust pressure drops lower and lower compared to ambient.  Because of all this, we had to make two compromises--first we had to run our tanks at a lot higher pressure than a pressure-fed system usually wants to, since at minimum throttle we still had to have something that wasn't so overexpanded as to run into problems.  The other compromise is we had to go with a much shorter expansion nozzle, for the same reasons.

If you took our existing Xoie vehicle, and had it go full-throttle in vacuum, it would deliver around 2600-2700m/s of delta-V.  If you gave it a more vacuum optimized nozzle, you could get it up into the 3300m/s range. 

Right now, our tanks are pretty overbuilt, because we both need a high chamber pressure due to low-altitude throttling operations, and because we are reusing the tanks hundreds of times.  By lowering the pressure to more typical pressure-fed values (which also happen to be around the minimum gage thickness for the composite tanks), and going with more traditional factors of safety, and with the better T/W ratio we're expecting with a 3k engine, it's quite feasible to pack 3-4x the propellant into a system that weighs about the same as Xoie without going to more advanced fabrication techniques.

Basically...at least in our case, you can actually get a lot more performance out of the system if you use it for an orbital-type mission than it can for low altitude hovering.

~Jon

With some modification, this could land on (or escape from) the Moon? Assuming I'm remembering correctly lunar ve is 2400m/s.

[jongoff]

With some modification, this could land on (or escape from) the Moon? Assuming I'm remembering correctly lunar ve is 2400m/s.

Lunar landing or ascent dV is ~2000m/s.  That's why they picked the 180s flight time for the LLC.  While our vehicles would have more than enough raw performance, there's a lot that goes into designing for long-duration in-space operations that we haven't even scratched the surface of yet as a company. 

~Jon