Debris, interference and SLS pad became main Space Ops talking points

by | Jun 18, 2012 | Seradata News | 0 comments

A Right Royal Start

With the help of some sweet renditions by the Prisma girl’s choir, the King of Sweden, His Majesty, Carl XVI Gustaf, opened the biennial AIAA Space Ops 2012 conference.  This conference is for those scientists and engineers most closely involved in the operating of spacecraft, both manned and unmanned.    As he did so, His Majesty mentioned the benefits of spacecraft monitoring in helping the world’s environment – a subject close to his heart.

Of course, Sweden’s space programme which is most strongly associated with launching sounding rockets from Kiruna, also has an interest in satellite technology via SSC (formerly the Swedish Space Corporation).   It was in this context that industry expert Sven Grahn even joked that his Majesty once put his name on the Astrid 2 spacecraft and then openly wondered “Who will read it?”  It was a fair point.

Overall the SpaceOps conference was well organised with some good opportunities to make social and business connections.  Stockholm is a very nice city as well.

The organisers even provided a free lunch in the exhibition area which pleased most and had two social events including one at the Vasa ship museum (surprisingly there are no aerospace museums in Stockholm) to which most were invited to.

As usual, by having several strands of lectures running at the same time, attendees found that they could not be in two (or three) places at once.  Nevertheless, given the strict session timing, most people got to see their main priority lectures in the timetable.     Below is just a flavour of the Plenary and technical presentations.  It was noted that some of the US presenters had to previously self censor some of their technical elements to get their presentations passed by their respective ITAR Export Control officers.

Debris and interference threats discussed

In the technical sessions the threat of debris (and how to limit it) was discussed.  Emmet Fletcher of ESA detailed how radar and optical data was being used to check against known object catalogues in the attempt to track new hazaardous objects and put them on a database.  Fletcher’s concern was that within 48 hours, the drag of the atmosphere could, depending on its density, change the track of an threatening object significantly.  His solution was to make more regular observations – though he admitted that more space and Earth-bound sensors would be needed for this.

Later in the conference, the subject of interference and jamming became a major topic of concern. Mohanned Elnour Ahmed of the Middle Eastern operator Arabsat noted that while only 10% of interference was deliberate it was becoming difficult to combat.  “The jamming of television signals cannot be stopped due to their nature.” he said as he noted how jamming had recently been done for both political and even contractual dispute reasons.

With respect to the future of commercial communications, interestingly Mr Ahmed predicted that the Geostationary orbit would lose its significance in favour of low Earth orbit constellations.

Human Spaceflight:  Where next?

During the human spaceflight and exploration plenary, Veno Seiichi of Japan’s space agency, JAXA, noted their plan to give the HTV cargo craft a return capsule capability.  Called HTV-R, this spacecraft could one day give Japan a human spaceflight capability as well.  Japan remains keenly interested in manned spaceflight.  Having pioneered the robotic arm berthing technique for the HTV (a technique which is now being used by SpaceX), JAXA is also working on high internal pressure space suit technologies that would elimiate the need for prebreathing.

When it came to the International Space Station’s robot arm, Pierre Jean of the Canadian Space Agency, noted that it was having to face up to “vendor obsolescence” as he noted the difficulties of getting parts and expertise for items that were no longer being made.

While it was currently having to rely on Russia to launch its astronauts, NASA’s Bill Gertenmaier described how testing of the Orion space capsule was proceeding satisfactorily and that acoustic testing was nearly complete.

In respect to where mankind should go next, Gerstenmaier warned that there may not be enough asteroids in close proximity to Earth to allow such a mission to take place.  He suggested that it would take more or less the same Delta V (velocity change) to reach Mars as it would to reach one of these and hinted that the Moon would probably be the next likely place to visit.

With respect to manned low Earth orbit operations, Gerstenmaier warned that while the commercial programme was cost effective, it had had to sometimes take big risks.  He gave the example the second stage of the Falcon 9 which was notd vaccuum tested until it was fired on its way to orbit.  Having noted that this testing short cut gamble paid off, he warned that this was not always the case.

Gerstenmaier also noted a word of caution about the prospects for commercial space travel systems.  I don’t think that space tourism is big enough to drive all the commercial companies,” he said, suggesting that hopes that space tourism would fill any shortfall in government business could be unfounded.

Atlas V lined up for commercial crew journeys while SLS pad may be reconfigurable 

With respect to commercial crew launch providers, while companies like SpaceX and Blue Origin one day plan to fly their craft off resusable launch vehicles, for the time they, along with Sierra Nevada, have chosen the Atlas V expendable launch vehicle to loft their spacecraft.  Mike Holguin of the United Launch Alliance noted in his presentation that any such rocket would likely need a dual RL-10 engine powered Centaur upper stage configuration.

NASA executives Jody Singer and Jerry Cook confirmed the running order of the initial flights of the Space Launch System (SLS),  The first flight dubbed EM-1 is to fly in 2017 using a Block 1 configuration (5 segment solid rockets and an RL-10 powered upper stage).  This 70 tonne payload rocket will project a “boiler plate” Orion capsule back into the Earth’s atmopsphere at 11km/s after its seven day flight around the moon.    In 2021, the first fully crewed Orion lunar flight will take place.  This flight called EM-2 will last 10-14 days and will use a J-2X powered upper stage.  The number of 290,000lb J-2X engines on the SLS upper stage has yet to be disclosed but it is likely to be one or two.

Before both of these flights, the EFT-1 flight aboard an Atlas rocket will carry the Orion capsule in unmanned configuration along with the SLS adapter.

NASA is concentrating on limiting operating costs as NASA’s Dr. Michael Watson noted. Having got wise to the concept that their current and future political masters are most interested in “costs now rather than costs past” the SLS team is concentrating on developing a heavy lift launch vehicle whose costs ot operate will be lower than past heavy lift launch vehicles.

When the team was asked whether the 130-160 tonne payload Block 2 SLS in the full two advanced booster configuration (either using advanced solids or liquid fuel boosters) could ever reach 200 tonnes in four booster configuration, Jerry Cook noted: “We could go to four boosters at a later stage but for the time being this is restricted by pad infrastructure.”

This was confirmed by Hector Delgado, Chief Engineer of Design and Developments at Kennedy Space Centre.   While he admitted that the mobile launch pad was being modified with a rectagular slot to take the main core and boosters of SLS, it would be difficult to get first stage refueling lines in and keep the structure stable if the “hole” configuration in the mobile pad was changed to a four booster one.

Likewise, as he noted in his paper that he was fully in favour of making the umbilical arms moveable on tracks on the launch tower to accomodate different sizes of SLS and even other launch vehicles, nevertheless, he noted that with only 50 feet (15.25m) of clearance, a safe launch of a vehicle using four boosters would be hard to achieve.  Delgado also noted the need to remove the umbillicals with certainty and with speed if unextinguisable/unthrottleable solid rocket boosters were used.

While Delgado was keen to increase the pad’s utilisation he had to admit that while it might only fly three times a year, SLS was always have priority over any other launch vehilces with designs on using the pad.

The NASA team also admitted that the flat spend on the SLS launch vehicle development has its own limitations, but they were making the best of it.  Hector Deglado was keen to note that to save costs, NASA was becoming adept at “using what they have” rather than building all new infrastructure and hardware.  For example, the main structure of the launch tower came from the now cancelled Project Constellation Ares launch programme, while the pad’s water suppression tanks are from the Shuttle programme.  Meanwhile the flame trenches originated fromt the Saturn V Apollo era.

New methods of fuel measurement and automatic reporting for satellites in orbit

While manned spaceflight and interplanetary missions offered the “sex appeal” of the conference, the run of the mill operations of commercial spacecraft continued to enlighten.

One interesting presentation by Boris Yendler of YSPM in conjuction with the Middle Eastern communications satellite operator Arabsat.  The YSPM consultancy has perfected the technique of using heating rates to determine the amount of propellants there is left on a spacecraft (in space conventional fuel gauges to not work).  The system was used to measure how much life was lost during an emergency manoeuvre on Arabsat 2B.

Richared Burley of NASA described the unfortunately named ARS (Automatic Reporting System) which automaticallly registered anomalies to the Hubble Space Telescope allowing ground controllers to do other things unless an urgent case came up.

While ESA/NASA Mars exploration ExoMars programme was torn assunder when NASA defected, the Moon is apparently still a place for space cooperation. China’s Chang’e 3 lunar rover which is due to be launched in 2013 will use ESA ground stations during its mission.  The rover is to carry a robotic arm.

Keeping ISS safe – even in an unmanned condition

After the cargo craft, Progress M-012M (ISS-44P), failed to reach orbit last year, the threat of having to abandon the International Space Station  made ESA and NASA update their procedures for keeping the station alive if it ever does have to be left unmanned.

Thomas Hiriart of CAM noted that that there was a trade off between risks in the procedures for doing this.  For example, switching off the fans inside Columbus module seems sensible from a fire safety point of view, until it was realised that for air safety, smoke detection and condensation reasons it was best to leave them on.

Meantime Andrew Cecil of NASA noted how experimentation on the International Space Station could now be controlled directly by users via the Ku-band transponders of  rather than by the S-band transponder system.  It was noted that suitable safeguards are in place to ensure station safety.

Unmanned exploration:  Electric thrusters are good but venting causes problems for comet hunters

Carl Brandon of Vermont Technical College announced that there would be a technology test flight in July for the “Vermont Lunar Cubesat” which would one day be flown to the Moon using Xenion Ion electric thrusters and might even use a ballistic capture trajectory.

The Cubesat test flight to a 500km, 40.5 degree inclination, low Earth orbit will be on a multi-satellite Minotaur launch vehicle in July 2013.

While using efficient electric propulsion an eventual cubesat misson round the moon is planned, there are downsides to using such technolgy.  For example, its low thrust means that it can take 23,000 hours to reach interplanetary velocities of circa 7km/s.  There are also some other mission limitations of having such a weak thrust.

One of the interesting papers presented was that of Richard Rieber of JPL as he disclosed the problems and solutions in approaching the Comet Hartley 2 during the EPOXI add-on mission. Specifically, comets doe not stand still as gas vents act as thrusters given them velocity increments in unexpected directions.  His advice for future comet missions is to have enough high thrust trajectory altering capability to make last minute corrections – and electric thrusters simply do not have enough impulse for this.

There were other problems on the mission Rieber noted.  EPOXI, in being an add-on mission to the original Deep Impact spacecraft, found that it had to slew itself backwards and forwards to acquire data and transmit it back to Earth during its approach to the Comet Hartley 2.

Earth Observation:  benefits yes but privacy remains an issue

While the Earth Observation plenary panelists from DLR, Eumetsat, DMC, Google Earth and CNES were keen to note how imagery from Earth observation spacecraft was helping mankind by monitoring the weather and volcanos, preventing genocide and even helping individuals decide which house to buy, but as imagery satellite and aerial imagery improves the issue of privacy remained a concern as was apparent from questions posted online from the audience.

As the experts went on to explain the advantages of the METOP satellite series for meteorology, it was noted that some data such as atmospheric pressure readings was usually much better recorded in situ.

It was then suggested by Ed Parsons of Google Earth that all smart mobile phones should carry satellite trackable barometers as an ap (application). He then quickly tried to reassure the audience that this information would be kept completely anonymous.  And some believed him.

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