Stage views

Views of a rocket launch from the perspective of the rocket stage are always intriguing.  They get even better when they use good quality sound and video from the flight itself.  For serious students of rocketry, there is a host of clues about the nature of flight to be gleamed from them.

In the last few days, a video which captures the launch of the Space Shuttle from the perspective of its Solid Rocket Boosters (SRBs) has been spreading in popularity on the web. Since I don’t use phrases like “This is awesome!” I won’t start here.  You will have to judge for yourself… which is the way I like it.

But before getting to that video, I thought it would be worth noting the efforts of one of the most successful small teams.

Armadillo Aerospace Stiga

Space and rocket launches have a way of attracting entrepreneurial computer scientists.  In this case, John Carmack, the lead programmer of Id Software, pulled together a team in the desert of Texas known as Armadillo Aerospace.  They initially set their sights on the Northrop Grumman Lunar Lander X Prize competition, and won the Level 1 in 2008, worth $350,000.  In 2009, they were upstaged by another small team, Masten Space Systems, which won $1 million in the Level 2 challenge.  Armadillo came in second, receiving $500,000.  (Here is a NASA summary of the Lunar Lander competition.)

Armadillo went on to do its own high altitude sounding rocket development as well as lander development for NASA.  Their Stiga rocket gained an altitude of 95 km (59 miles) on its second flight. A ballute (somewhere between a balloon and parachute) was deployed as part of the recovery system, providing aerodynamic drag before a main chute was deploy. Unfortunately, a strap attached to the ballute broke.  The result was the rocket barreling into the ground at high speed.  Armadillo has been amazingly open about their successes and failures, providing a way for others to learn from their experiences.  Their summary on flight 2 of Stiga is here.  Their video (with sound) of the flight is below.

Armadillo went on to build Stig B.  However, following a launch failure of the rocket, the team is currently in hibernation.

Shuttle SRBs

A DVD/BluRay volume celebrating the Space Shuttle from NASA Glenn is being finalized.  However, a sneak peak has been uploaded to YouTube.  The sound and video come from cameras and microphones on the Shuttle SRBs. The sound quality has been enhanced by Skywalker Sound, but it is all sound from the SRB mics.

The upper right corner of the screen presents the speed of the vehicle.  One of my favorite moments is watching it transition through Mach 1, just above 700 mph.  It is one of the best view of breaking the sound barrier that I have seen anywhere.

About 123 seconds into flight, the SRBs are still burning, but main force and fury of the stages is already spent. The mics manage to capture the metallic groans of the stages shortly after separation from the Shuttle Orbiter and main tank, still on their way to orbit.  A ultra-bright light is seen as the SRBs fall away — the engines of the Shuttle Orbiter as it continues to orbit.

Since there are two SRBs, one is able to capture the free fall of the other.  As they reach the atmosphere, one is able to see the disintegration of the booster engine of the other.  Finally, there are loud pops as the main chutes are deployed, and the splash as they hit the Atlantic ocean — cameras and mics still recording.

The video was posted by Michael Interbatolo, an engineer and project manager at NASA Johnson Space Center by day who experiments in leading edge media technologies by night.

Translation experiments

There are, of course, other “cool” rocket videos on YouTube.  Of particular significance are demonstrations of translation, that is, controlled lateral (sideways) movement.

  • SpaceX recently demonstrated this with their Grasshopper reusable booster development. SpaceX confirms that no cows were injured in this test.
  • Masten has provided its Xombie rocket as a guidance, navigation, and control (GNC) test bed for other groups, such as JPL.  (Bonus compilation, including views from the rocket itself as well as the landing area, with the rocket coming toward you.)

Close approaches of NEAs

How frequently do near Earth asteroids (NEAs) closely approach Earth?  Usually, NEAs only show up in the news media if they are very close and very large, or they impact a populated area.  There are, however, many more that make close approaches, but safely pass by the Earth.  Some of these may be candidates for possible mining.

If we want to select asteroids for possible mining, then the ideal candidates are those that come close to Earth slowly, but don’t hit, and are sizable to allow for extensive mining.  How frequently do candidate asteroids show up?

JPL maintains a table of NEO close approaches (NEO = near Earth object).  The table describes close approaches for the next 60 days.  I abstracted from the table today (August 23, 2013) to see how frequently these occur.

Here are some sizable asteroids that have velocity < 10.0 km/s relative to Earth, and < 20 LD (lunar distances) at close approach.

ID Date Distance Speed Diameter
LDs km/s meters
2007 CN26 Aug 28, 2013 11.9 6.85 170 – 380
2008 PW4 Aug 30, 2013 14.3 6.77 90 – 200
2010 CD55 Aug 31, 2013 17.9 6.13 64 – 140
2010 CF19 Sep 9, 2013 14.9 8.37 130 – 290
2002 NV16 Sep 30, 2013 13.9 4.27 140 – 310

As a point of comparison, the velocity needed to reach low Earth orbit is about 7.9 km/s.  Escape velocity is 11.2 km/s at the surface of the Earth.  What this means is that a probe from Earth to one of these NEAs would spend the majority of its velocity change (delta V) just leaving the Earth.

The uncertainty of diameter is substantial, which means we don’t have a good handle on mass.  Rendezvous/loiter near these objects would help determine mass and shed light on their make-up.

The relatively low close approach speeds means that these orbits are not highly elliptical.  They are likely to be generally in the Venus-Earth-Mars system.  Faster speeds would indicate more energetic orbits which might take them to the outer planets (or at least to the main asteroid belt).

There are a lot of asteroids which are farther or passing by much faster.  Those would take more energy to reach than these, and thus I did not include them.  There are also many that are smaller, and thus not much mining to be done.  So, given the table for the next 60 days, these are the ones that might make prime candidates for rendezvous missions.  Extrapolating to over a year’s time, there might be 50-60 asteroids each year that might be worth visiting as mining candidates.

Nanosatellite launchers – works in progress

As instruments such as image sensors get smaller, cheaper, and yet improve in performance, they open up possibilities for very small satellites.  Of particular interest to me are nanosatellites (under 10 kg) and microsatellites (under 100 kg).  To date, these have been launched as secondary payloads on rockets carrying extremely expensive primary payloads.

To simplify the integration of low-cost small satellites, Prof. Jordi Puig-Suari of Cal Poly Luis Obispo and Prof. Bob Twiggs of Stanford University came up with a standard framework known as a CubeSat.  It is no understatement to say that it has revolutionized the design and deployment of low-cost small satellites.

CubeSat_in_handStandard 1U CubeSat nanosatellites are exactly 1 liter in volume, 10 cm on a side, and have mass of up to 1.33 kg.  A 2U CubeSat is 20x10x10 cubic cm, and up to 2.66 kg.  A 3U is 30x10x10 and up to 4.0 kg.  They typically fly in very low orbits, and may re-enter and burn up in a matter of weeks or a few years.  Thus, their design life-times are adjusted accordingly.

Because they fly as secondary payloads, they are subject to the rules of the typically very expensive primaries.  Launches can be anywhere from months to years away.  But increasingly, they are first flown to the International Space Station, and then released into a trailing orbit behind it.

The case for nanosat launchers

I have previously posted my thoughts about the business case for a nanosat launcher. I believe the premises for a business case still hold.  In fact, I am beginning to see increasing evidence of interest.

The purported benefits of a nanosat launcher include:  better control over launch window, selection of orbital plane/trajectory, no risk to a more expensive primary payload, no risk to humans on the ISS, option to test exotic propulsion systems.

Current launch costs of payloads are fairly high.  But in my view, the greater impediment to broader access to space is schedule.  If launches can be arranged weeks or days in advance (instead of months or years), it then becomes possible to build an iterative research and development cycle where payloads are designed for a month or two, launched and monitored for a month, and then a new experiment is developed in another month or two while continuing to digest results from the current one in orbit.  Researchers do not go off to another two or three projects while waiting for this one to launch again, and then come back and have to restart their research efforts.  A company can conceivable fly 4-6 times a year, and dramatically shorten their research efforts.

(Who would do this?  There are a variety of effects in microgravity or vacuum conditions which can be utilized.  Going through these is a separate subject, and is more suited to those researchers who might benefit from them.  So I won’t belabor those here.)

Quiet trends

Why do we not hear more about these?  The major media will not be reporting on nanosat launchers because the big space issue is how the US will launch its own people into space.

Among the trends quietly emerging is the use of the International Space Station as a launch platform for nanosatellites.  All the requisite safety checks apply.  But there is a regular schedule of launches to the ISS every two months, bringing food and other supplies.  Payload integrator NanoRacks has effectively gotten the checks and procedures into a reliable business cycle.  There are limits on what can be flown to the ISS.  Even though a CubeSat is intended for launch from the station, it still needs to be handled by the crew, and there has to be iron-clad assurances that no small incident would precipitate a major emergency on the station.  NanoRacks has been so successful at this that they have received an ISS Innovation Award from the American Astronautical Society.  (The major innovation is really in bringing small experiments into the ISS on a regular basis.  Nevertheless, the same principles apply to satellite deployment from the ISS.)

The ISS is not necessarily in the ideal orbit for deploying satellites.  It occupies one orbital plane.  It cannot handle orbits which are more polar or more equitorial.  These still require separate launch vehicles.

A case is arising for asteroid mining, or at this stage, prospecting.  The chances of a primary payload being aligned with a passing near-Earth asteroid are extremely slim.  Companies like Deep Space Industries would like to fly lots of prospecting CubeSats to lots of asteroids.  A launcher on which their probe is the primary payload can greatly simplify the logistics of prospective.

Who is working on nanosat launchers?

NASA released an SBIR Select topic for nano/microsatellite launch vehicles in 2012; these are expected to loft 20 kg into a circular (possibly polar) orbit at 400-450 km altitude. DARPA has selected teams to develop vehicle technology for an microsatellite (up to 45 kg, 100 lb-m) air-launch vehicle (ALASA: Airborne Launch Assist Space Access).

  • DARPA ALASA has now funding five companies’ research studies. In addition to them, Virgin Galactic is a non-funded ALASA participant, and is now working on LauncherOne, using the same launch platform as SpaceShipTwo.
  • US Army and NASA are working on SWORDS.  A tactical nanosatellite launch due for flight test in 2014.  Payloads will be up to 25 kg.
  • Small satellite company Microcosm spun off Scorpius to solely focus on rocket technology they had developed.
  • When XCOR matures the Lynx rocketplane to Mark III, its dorsal pod is intended to house a nanosatellite launcher.

There are also smaller efforts with varying degrees of hardware development.  Among the notable is the Microlaunchers effort of Charles Pooley.  Charles prefers a grassroots movement that is akin to the PC revolution.  He believes in a cadre of people building skills from the ground up.  He has at least done a propulsion test.

There’s also me, with no hardware, some conceptual designs, and a bit of simulation.  I’ve spent too much time in recent years among pilots and aerodynamicists; they smile when I say air-launch. But then I tell them my design is premature; I am very direct about the holes that need to be filled in before a credible design optimization can be done.

My personal suspicion is that one of the dual-use plans, where the support infrastructure is also used in another business model, will be the one that succeeds. That means possibly XCOR, Virgin, or even my crazy air-launch scheme. However, Charles may win the award for lowest cost, if he can win the grassroots people over.

Curiosity on Mars – remembering 7 minutes of terror

It was a year ago, on August 5, 2012, that Curiosity – a rover the size of an SUV – survived what its designers nicknamed “7 minutes of terror”, including a new landing technique known as the Skycrane maneuver.  Prior to the landing, the world was introduced to the video which portrayed the complexity of the landing problem.  Fundamentally, Curiosity was so much larger than previous rovers that it could not land using the same techniques, which often involved inflated thick-skinned balloons bouncing several times before coming to rest.  Curiosity was just too large.  A new series of engineering tricks had to be invented, and each trick had to work in succession until the rover was landed on the surface of the planet.

Mission control at JPL about 15 minutes before landing.  Viewed on big screen at NASA Ames.

Mission control at JPL about 15 minutes before landing. Viewed on big screen at NASA Ames.

In some locations, NASA hosted gatherings for people who wanted to see the landing live. These sites had direct feeds from JPL.  I attended the outdoor event at NASA Ames with 6,000 other people.  The accompanying photos were shot of the big screen (about 20 feet tall) of the JPL video feed.

NASA Ames had a vested interest in the landing because the heat shield tiles were developed there.  Once on the surface, the CheMin (Chemistry and Mineralogy) experiment from NASA Ames would analyze samples of the Martian soil.  Assuming, of course, that all the parts of the automated complex landing process would actually work.  While lots of testing was done on Earth, there are some conditions of a Martian landing that simply cannot be duplicated extensively.

2012-08-05_22-27-40_680

902.7 meters/sec, Mach 3.8, 18.62 km altitude. Aiming for the landing ellipse.

The atmosphere on Mars is 1/100th the density of the atmosphere on Earth.  Nevertheless, entry into the Martian atmosphere at interplanetary speeds (an equivalent of escape velocity, but in reverse) piles on combined heat and deceleration G forces for several minutes.  On Earth, you can heat a sample of material for an extended period.  You can generate G forces separately for the same period.  But you can’t necessarily do both together.  You hope that there is not a failure mode that only exists when the two work together.

2012-08-05_22-32-09_880

0.7’6 meters/sec, 18.71 meters altitude. A few seconds from landing.

The newest innovation in the landing was the Skycrane.  After the heat shield was jettisoned, the Skycrane cradling the rover would deploy, and rocket off to the side.  If it were to go straight down, chances are that the parachute and aeroshell that it had just separated from would continue down and impact the vehicle. Thus, the first order of business was a collision avoidance maneuver.

As it neared the surface, the rover was winched  down, unwinding several meters of cable to provide a distance between the Skycrane and the rover.  The objective was to minimize the blast of the rocket engines on soil and loose rocks of the Martian surface, thus minimizing potential damage to the rover.  Once touchdown was detected, the rover had to disconnect the cables holding it to the Skycrane, leaving it to rocket away into the distance.  All of the cables had to release, all at the same time.  If one cable did not release, the unbalance would send the Skycrane gyrating into the ground, not far from the rover, probably destroying it in the process.

Understandably, for the designers of the EDL system (EDL = entry, descent, and landing), the time period from atmospheric entry to touchdown and release was sheer terror.  After that, the designers of the instruments get to worry if their handiwork survived the trip.

If you don’t remember the seven minutes of terror, and what it represented, here is a video reminder.

As this writing, a year after landing, Curiosity has fired over 75,000 laser shots at the soil to facility spectrographic analysis.  It is taken over 70,000 images, and has sent nearly 200 gigabytes of data back to Earth.  The rover is on its way to Mount Sharp, a mountain that shows several geological layers, including ones that indicate a once wet environment.

Curiosity has been so successful, that a new rover of similar design will be launched in about 7-8 years.  Meanwhile, a series of smaller spacecraft will be sent to Mars to study the planet.

ArduSat-1 takes flight

ArduSat-1 and ArduSat-X have hitched a ride on the JAXA HTV-4 transfer vehicle to the International Space Station.  The H-IIB rocket carrying the the HTV-4 was launched at 2013-Aug-04 04:49:46 Japan Standard Time (JST).  (See time conversions below .)  Frankly, I did not know that there was an ArduSat-X.  I am delighted to see that the team has been able to build and launch two spacecraft instead of one.

I was fortunate enough to co-host a presentation on ArduSat about a year ago through the Small Payload Entrepreneur TechTalks co-sponsored by the Silicon Valley Space Center and the AIAA San Francisco Section.  [Here’s the meeting announcement on  NanoSatisfi: Citizen Apps in Space.]

Ardusat architectural diagram

ArduSat is designed and built by NanoSatisfi, a small start-up company whose tagline is “Affordable Access to Space” TM. (Yes, apparently that tagline is their trademark.)  ArduSat is a platform for multiple small experiments in space, packaged to the CubeSat form factor and driven by an Arduino microcontroller.  It doesn’t use Arduino boards directly because those are not designed for space, but the chip is an Arduino microcontroller.

Major funding for the project was raised on KickStarter.  A number of interesting gimmicks enticed people to bigger and bigger pledges, including a set of Science Cheerleader Trading Cards or your initial on the spacecraft.  At the $150 mark, you could steer the spacecraft and take pictures.  At $325, you could run your own custom science experiment or application for 3 days.  At $775, you could take advantage of the Advanced (rather than Standard) sensor suite on the spacecraft.

Because ArduSat is built from commercial off-the-shelf components, they were able to keep component and fabrication costs relatively low.  The life-time of the satellite on-orbit is expected to be perhaps a year, but this is anybody’s guess.  The components are going into the vacuum of space, where many typical commercial components outgas and fail soon after.  It is below the van Allen radiation belt; so they are not being exposed to the harsh radiation environment of geostationary satellites.  but some stray radiation particles may still hit, causing processor resets.  There will be severe heating and cooling of the spacecraft in 90 minute cycles.  It will be interesting to see just how long the processor and the experiments will last.

Because ArduSat is being deployed from the International Space Station, it’s orbit has a fairly good apogee.  The life-time the spacecraft will depend heavily on how low perigee gets; that is, how deeply it gets into atmospheric drag.

Within a year or two, a new generation of sensors, radios, microcontrollers, and other components will reach the commercial market.  These new components will make those on ArduSat-1 obsolete.  ArduSat-2 would be a new satellite, built with the newer components, once again at low cost.  If demand keeps up, and too many individuals or groups want to run experiments, then they may have no choice but to build more satellites and make more profit.  That would be a wonderful problem to have.

For NanoSatisfi, the launch is perhaps the easy part.  They had an engineer on-site at JAXA for integration, but the launch was really a JAXA affair. Now the real fun begins.  They will see if the spacecraft works after deployment from the ISS.  This will be the real test of whether NanoSatisfi’s technical efforts have paid off.

CubeSats and Kickstarters

Two other pioneers used Kickstarter to fund CubeSat projects.  Both are scheduled for launch next year.

  • KickSat – the original granddaddy of this genre of projects.  This project really uses a CubeSat to house and spin out hundreds of “sprites”, small picosatellites that do things like monitor the upper atmosphere.  The sprites were conceived at Cornell University.  A funding crisis on the project forced project lead Zac Manchester to look for much more creative sources.  Because the project was part of work done at Cornell, it is being manifested for launch in the NASA ELaNa program.
  • SkyCube – an offshoot of the highly successful SkySafari app for Apple iOS devices.  The project allows funders to take pictures from space or send short tweets.  After its useful lifetime, it will inflate a 10-foot reflective balloon, making it very visible and increasing atmospheric drag to de-orbit it in a few weeks.  There is a vague chance that it will launch this year on an Orbital Sciences Cygnus/Antares, which does not yet have a proven track record.  The team may instead opt to fly on the SpaceX CRS-3 mission in early 2014.

In the last few weeks, the concept of raising spacecraft funds on Kickstarter has been used by asteroid mining company Planetary Resources to push up development their Arkyd space telescope.  Doing so, they raised over $1.5 million.

Time conversion

For the time-challenged (like I sometimes am), here’s the conversion of launch time from JST to some selected timezones:

2013-Aug-04 04:49:46 JST
2013-Aug-03 19:49:46 GMT
2013-Aug-03 15:49:46 EDT
2013-Aug-03 12:49:46 PDT

NanoSatisfi has posted the HTV-4 launch video on YouTube.