Micro-Space >> Ultralight Manned Spaceflight

[rpspeck]

Lampyridae - 24/3/2008  10:54 PM

rpspeck - 5/2/2008  6:54 AM

Lampyridae - 4/2/2008  7:53 PM

Assuming you use STP coupled with ammonia propellant (Isp 600s or so) ...

I appreciate the suggestions about Solar Thermal Propulsion.  The big problem I see with it is that it misses the Oberth Effect (Gravity Well Synergy).  It may offer 600 sec ISP at LOW thrust, but acceleration near Earth gives up to a 5x multiplication of Delta V, and cancels the advantage of STP.

Oberth effect only applies for slingshot burns, not for actually leaving orbit. It helps make your trip shorter by a bit.

The Oberth effect benefit is available anytime Delta V can be added while deep in a gravity well.  The gravitational energy increases the vehicle velocity, and this increases the Energy added by the Delta V acceleration.  {KE = 1/2MV^2 = 1/2M(V1^2 + 2V1DeltaV + DeltaV^2)}Since Energy (not velocity or momentum) is conserved when your orbit carries you out of the gravity well, this multiplied energy gain adds to "V Infinity" and C3, a very desirable result.  If you must break your acceleration into multiple steps, most of the benefit can be retained by accelerating only near perigee (periapse in general) in an expanding, highly eccentric orbit with small periapse distance.

By flying near circular, expanding spiral orbits, the velocity steadily decreases and the ENERGY added by each DeltaV increment decreases.

Much of this benefit can be retained if Delta V is limited to a 1000 second window around perigee.  This is a reasonable amount of time.  The cyclic addition fails when escape velocity is exceeded, so that the last 400+ meters/second of Delta V (producing 3Km/sec V Infinity) must be added in one of these acceleration windows.  

Acceleration near periapse limits the DeltaV required to the difference between circular orbital velocity and escape velocity (plus that required to get the desired V Infinity or C3). The cumulative Delta V required in a slow spiral is much higher as the energy added when the orbit spirals past the Moon, for each increment of Delta V, is less than 1/10 of what it was close to the Earth (and does not exceed that calculated above at any part of the orbit).

[rpspeck]

Surprise and Progress

Surprise: Virgin Group and Google announce private Mars expeditions and colonies:  “Project Virgle”.
(April 1, 2008)

http://googleblog.blogspot.com/2008/04/announcing-project-virgle.html

It is disappointing that a private Mars expedition has to be part of an “April Fool's Joke”, rather than a real announcement!  As outlined in our other BLOGS, a pioneering Mars expedition can most certainly be funded by a corporate sponsor.  But, of course this means a minimum cost effort to show that the risks of such expeditions are manageable, and that commonly suggested  mass and dollar budgets are  grossly inflated. (The fictitious “Project Virgle” goes far beyond these minimums!)

For comparison, I invite any interested party to estimate the cost and schedule of perfecting a Cable Car to the top of Mount Everest so that this popular terrestrial objective can reached with “Reasonable Comfort and Safety”.   Should we limit access to remote parts of our planet and solar system to adventurers or should we make access to them “OSHA” compliant?

Does the discovery of unexpected resources or scientifically interesting anomalies still depend on adventurous souls willing to tolerate risk and privations to “go where none have gone before”?  If it does, then I have in fact found a few individuals willing to go (through "Astronauts Wanted")!



Back on Earth, Progress at Micro-Space continues. About 7 of the 14 Liquid Fuel  Rocket Motors in our new batch are ready to run.  Work continues on the others.  

We are modifying our motor test system to run these higher thrust, long burn duration motors.  In this process we are actually integrating much of the flight hardware and plumbing into the test system, so that it will become more of a “Hot Fire Test” of the flight system than an isolated motor test.  At the same time we are finishing the plumbing and other hardware in our first two flight ready “Lunar Landers”.  These will soon be operating in tethered flight.

Micro-Space is actively investigating the launch services of “UP Aerospace”,   http://www.upaerospace.us.com , since this organization offers relatively affordable space launch.  Use the small number of paying customers served to date by this company as a warning about promoters who tout suborbital vehicles for “unmanned Zero G and Space Research”.  That market is extremely small,  and  can be well served by operational UP Aerospace Launch Vehicles.  Better, in fact, than by piloted suborbital vehicles because the experimental systems themselves can add risks and always do so if they include propulsion systems.  It is much less expensive to test a risky space propulsion system on top of an expendable rocket than carried by a very expensive, piloted vehicle.  And that is exactly what we have in mind.  

We claim, and will strive to prove, that our present Lunar Lander systems can be used in space and fulfill the requirements of the Google Lunar X Prize.  At 1/100 the lowest present cost for an orbital space launch, we can demonstrate and document the performance of our propulsion and control systems in near orbital flight, using the UP Aerospace “SpaceLoft® XL” vehicle.  

The “SpaceLoft® XL” vehicle can carry our  fueled Lander well above the atmosphere, proving in  the process that it can tolerate large launch stresses.  Several minutes in free fall is available for preignition  procedures, and then space ignition of our rockets will be demonstrated.

Although neither orbital flight or escape velocity will be achieved, our Lander can then accelerate to above 3 km/second, achieve over 600 km apogee and demonstrate motor re-starts, attitude determination and control and other maneuvers for over 10 minutes in space.  All communication procedures can also be tested and documented, including radio links between detached systems.  Thus the performance of all our critical space systems can be validated in a low cost flight.  The suborbital test can provide more Contiguous test time (with uninterrupted radio contact)  than a low altitude orbital flight.  

As always, Micro-Space is looking for ways to “whittle down” the cost  of proving our systems in space so that the risk faced by a “Competition Flight Investor” is reduced.  Micro-Space Lander flights in the next few months will be a major step in this process.  

[savuporo]

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

Thats about 1.5 weeks from now then, yes ?

[A_M_Swallow]

savuporo - 5/4/2008  10:04 PM

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

Thats about 1.5 weeks from now then, yes ?

I hope Rpspeck posts a link to a video of the test on youtube.

[Lampyridae]

tnphysics - 4/4/2008  1:43 PM

1. Magnetic fields don't provide protection against polar radiation.

2. Superconductors with Tc>120K have not yet been created.

1. Polar radiation? Do you mean charged particles coming in at the N or S poles? Yes, this is a problem. However, I believe the solution is to make the spacecraft in a torus shape, or arrange the modules such that ions pass through, say, a fuel tank. I think they refer to this as a magnetic lens shield. Early days yet, but I'm going to carry on digging.

This is a wealth of information:

http://engineering.dartmouth.edu/~Simon_G_Shepherd/research/Shielding/index.html

2. Current world record is 138K with a "thalium-doped mercuric cuprate," although other sources cite ~125K... YMMV, it'll take a major breakthrough for room-temp superconductors.

[Lampyridae]

Whoops, looks like I was getting the wrong idea. It seems the idea is to defocus the incoming solar protons so that the area behind the torus is less saturated (the protons spreading out in a cone after passing through the torus). Of course this does nothing for omndirectional galactic cosmic radiation, but it does deal with most of the rads.

[tnphysics]

Lampyridae - 7/4/2008  12:53 AM

tnphysics - 4/4/2008  1:43 PM

1. Magnetic fields don't provide protection against polar radiation.

2. Superconductors with Tc>120K have not yet been created.

1. Polar radiation? Do you mean charged particles coming in at the N or S poles? Yes, this is a problem. However, I believe the solution is to make the spacecraft in a torus shape, or arrange the modules such that ions pass through, say, a fuel tank. I think they refer to this as a magnetic lens shield. Early days yet, but I'm going to carry on digging.

This is a wealth of information:

http://engineering.dartmouth.edu/~Simon_G_Shepherd/research/Shielding/index.html

2. Current world record is 138K with a "thalium-doped mercuric cuprate," although other sources cite ~125K... YMMV, it'll take a major breakthrough for room-temp superconductors.

Okay. That's what I ment.

[tnphysics]

Lampyridae - 7/4/2008  12:53 AM

tnphysics - 4/4/2008  1:43 PM

1. Magnetic fields don't provide protection against polar radiation.

2. Superconductors with Tc>120K have not yet been created.

1. Polar radiation? Do you mean charged particles coming in at the N or S poles? Yes, this is a problem. However, I believe the solution is to make the spacecraft in a torus shape, or arrange the modules such that ions pass through, say, a fuel tank. I think they refer to this as a magnetic lens shield. Early days yet, but I'm going to carry on digging.

This is a wealth of information:

http://engineering.dartmouth.edu/~Simon_G_Shepherd/research/Shielding/index.html

2. Current world record is 138K with a "thalium-doped mercuric cuprate," although other sources cite ~125K... YMMV, it'll take a major breakthrough for room-temp superconductors.

Okay. That's what I ment.

[savuporo]

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

Just one week to go ! Will we get a press release next thursday ? Preferrably with videos and high-res photos of course.

[tnphysics]

What about IOC? (assuming adequate funding)

[savuporo]

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

This is going to be tomorrow ! im so excited ! i mean, after years and years in being engaged in all possible competitions, miles worth of in-depth discussion of various advanced concepts and so on, Micro-space is going to achieve lift off finally !
i hope nobody misses the big event, and im sure there will be videos and pictures and all.

[Patchouli]

tnphysics - 8/4/2008  5:41 PM

Lampyridae - 7/4/2008  12:53 AM

tnphysics - 4/4/2008  1:43 PM

1. Magnetic fields don't provide protection against polar radiation.

2. Superconductors with Tc>120K have not yet been created.

1. Polar radiation? Do you mean charged particles coming in at the N or S poles? Yes, this is a problem. However, I believe the solution is to make the spacecraft in a torus shape, or arrange the modules such that ions pass through, say, a fuel tank. I think they refer to this as a magnetic lens shield. Early days yet, but I'm going to carry on digging.

This is a wealth of information:

http://engineering.dartmouth.edu/~Simon_G_Shepherd/research/Shielding/index.html

2. Current world record is 138K with a "thalium-doped mercuric cuprate," although other sources cite ~125K... YMMV, it'll take a major breakthrough for room-temp superconductors.

Okay. That's what I ment.

You don't need room temp super conductors for a mag shield in space the shadow side of the vehicle will be cool enough to allow a very small refrigeration system to keep said super conductors cool.

As for making the hab a torus that might be good in two ways getting rig of the polar radiation and providing a shape one can spin for artificial gravity.

Though the microspace concepts are light weight and use of a tether and a spent booster stage as a counter weight would be more in alignment with the mindset behind low mass spaceflight.

Maybe even use an inflatable tube instead of a tether and turn the spent stage into more hab space.

The hab and spent stage just rotate about their common center of mass this is what Zurbin used for early work.

Even the plasma beam if it gets built might work with some ultralight concepts since the beam and power source don't travel with the ship.

I feel they would not violate the concept of very low cost but it would make the trip a lot faster and would solve the radiation issue by reducing exposure time.

[tnphysics]

So would a VASIMR.

[savuporo]

savuporo - 16/4/2008  11:47 AM

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

This is going to be tomorrow ! ...

Uh, four weeks have come and gone, and no liftoff ?? Micro-space couldnt have let us down now ? I mean, i had friends invited over for a party and everything.

[tnphysics]

Was there a delay?

[rpspeck]

Lowering the Credibility Threshold

As mentioned in my GLXP BLOG last week, Micro-Space and every other Google Lunar X PRIZE team will have to break through the “Credibility Barrier”.  It will take both an interesting financial “Up Side Potential” and a fair Chance of Success to attract investors for these projects.  The “Chance of Success” will be judged by each individual investor, and the credibility of each team's plans and promises, supported by relevant achievements, will be a critical factor.

Micro-Space has spent this week investigating low cost options for space testing in detail.  The price for the standard UP Aerospace “SpaceLoft XL” flight is $250,000.  At about 1/30 the cost of the least cost orbital service (with the Falcon 1) this radically lowers the threshold for producing an extensive demonstration of our “Lunar Lander” hardware flying in space.  On top of the cost saving is the fact that the SpaceLoft system is operational and has achieved its promised flight performance.  I am confident that SpaceX will also succeed, but when will that company be ready to fly customer payloads?  

In the real world, the chance of imperfect test results must also be faced.  With a test cost of  $250K, several attempts could be absorbed into our low ($10 Million) project budget if necessary.  Since the SpaceLoft XL can carry 110 pounds of payload (50 times the CubeSat limit), multiple flight components and subsystems can be included and  partial, if not complete, test success is very likely.  These test systems can also be full size modules from the Micro-Space “Lunar Lander” system, which avoids specialized development and guarantees that results are representative of modules in our Google Lunar X PRIZE competition system.

The SpaceLoft XL flight will allow ignition and restart of our rocket motors to be well documented in the  vacuum, zero G conditions that exist near the Moon. Predicted motor performance and temperatures can be verified. The attitude determination and control functions can be documented in a series of maneuvers coordinated with the motor firings.  Performance of our optical navigation systems can be verified in space as well as the radio and tracking links.  A wide range of other details will be verified as well, from launch load tolerance to zero G fuel settling procedures.

Micro-Space has made a serious effort to maximize the “Up Side Potential” of our project, by making human transport to the Moon an integral part of our development and maximizing the research potential of our unmanned exploration system on the Moon or Mars.  The addition of suborbital spaceflight for the testing phase radically reduces the investment required to demonstrate spacecraft capable of reaching the Moon.  Proven spacecraft systems, combined with multiple spacecraft in a Falcon 1 payload,  make the success of a Micro-Space competition flight highly likely.  

We are still working out the details of our spaceflight tests with UP Aerospace, but the addition of these modest cost tests radically improves the Risk/Cost pattern for the Micro-Space Lunar program.  

[rpspeck]

savuporo - 18/4/2008  1:51 PM

savuporo - 16/4/2008  11:47 AM

rpspeck - 17/3/2008  9:25 AM

We expect to achieve liftoff (in tethered flight) in about 4 weeks.

This is going to be tomorrow ! ...

Uh, four weeks have come and gone, and no liftoff ?? Micro-space couldnt have let us down now ? I mean, i had friends invited over for a party and everything.

Have we set a new president in spaceflight?  There has been a delay.  Not a specific delay, but a lot of little things that needed fixing or enhancement.  This morning we were preparing and upgrading our test site.  We are doing final preparation for the hot fire test (with thrust and other monitors) which will be our first run with the flight ready hardware.  The tethered flight test will follow soon: how soon does depend on the hot fire test experience.  

For comparison with other teams – keep in mind that our basic bipropellant propulsion components have been flown in 17 flights (one of which is viewable on Youtube). I know of only one other team which has achieved multiple flights of a bipropellant, liquid fuel system capable of competing in the NGLL Challenge. We don't like delays, but our progress and accomplishments are good.

[savuporo]

rpspeck - 18/4/2008  11:53 AM
Have we set a new president in spaceflight?

I believe you meant "precedent". Spaceflight as an activity isnt presided over.

There has been a delay.

A wild, guess, two days, a week, two years ?

We are doing final preparation for the hot fire test (with thrust and other monitors) which will be our first run with the flight ready hardware.  The tethered flight test will follow soon: how soon does depend on the hot fire test experience.

Any photos, videos or stuff with your test stand and hopefully hot fire ?

[dsky]

Jim - 1/2/2008  3:09 AM

rpspeck - 31/1/2008  8:52 PM

(This won't work if they don't want to see you!) Several GPS units are presently used on ISS.

But not "directly" linked to a radio.  The shuttle doesn't use it

ATV received DGPS info from the ISS for RGPS navigation.
I am surprised that this point has been missed.

The Shuttle is way behind in using GPS and should not be considered a worthy example.

Related to the topic, typical DGPS with low data rate WAAS/EGNOS overlay should be more than sufficient for ISS rendezvous. No need for high precision GPS (RTK) or other more bulky or current demanding systems. Using WAAS/EGNOS offers also RAIM (integrity monitoring) and the system can be used for all nav purposes even during re-entry and final descent on chute. WAAS/EGNOS augmentations are now qualified for airliner Cat I approaches.

The KURS system can also be used in its basic functions for guiding/monitoring the approach to the ISS from any angle, at closer ranges. All the onboard electronics can be easily miniaturized for this purpose.

And for a direct ascent (M=1 profile in the Gemini program, if I well remember) the ATV final approach seems the more reasonable (from the -VBar). If the promise of low dispersions is maintained of course.

This topic is very interesting.

[rpspeck]

New Rocket Motors Running VERY Well

Micro-Space accomplished its first “Hot Fire Test” in our upgraded test facility today.  As noted previously, this setup allows much of the flight qualified hardware to be tested in an integrated configuration.  This includes fuel level monitors for preflight and inflight monitoring, a new, lightweight ignition system, and a  system to enhance the reliability of our motors in “Rapid Restart” situations. The instrumented thrust range has also been tripled to allow testing higher thrust motors, and the fuel system has been reconfigured to make the documentation of consumed fuel mass more accurate.  The bipropellant systems have also been configured for more rapid loading, and expeditious unloading of fuel (the later is required for NGLL flight operations, so that the vehicle can be transported safely after a scrubbed flight).

Today's test in many ways repeated a previous test with a slightly modified motor design.  Again, the motor started immediately and came up smoothly to the intended thrust.  With different illumination, this is the first time that we have been able to see (and photograph) clear “Mach Diamonds” in our nearly transparent exhaust jet.  The “Diamond” spacing responded as predicted to throttling and our motors again demonstrated more than a 5 to 1 throttled thrust range.  

Predictable thrust with this new production motor, combined with excellent ignition and smooth throttling leave no propulsion problems for our “NG Lunar Lander” competitor.  We will be defining our delivered ISP more accurately soon, but it is already sufficient for our planned, 90 second hover Lander.  Good results with this new production batch of motors already gives us sufficient thrust, from a small cluster of motors, for our HTS (Human Transport System).  Tests of this could come as little as two months after flight testing of the “NG Lunar Lander”.  As previously noted, since these propulsion systems use storable fuels (Hydrogen Peroxide and Methyl Alcohol) they can also be used on the Moon for the Google Prize, and for the “Lunar Transfer” flight from LEO.

The thrust vectoring we use for control is already operational for the flight ready vehicle, as are the accelerometer and gyro subsystems.  We have done extensive modeling of the “Hover” control dynamics, and of course this effort builds on our analysis and successful flight of three “Finless”, near hover guided rockets more than a decade ago.  Much system's integration work remains to be done of course.  Very soon we will start posing new Video of Tests on YouTube.