Why this space ride won’t be so rough
Russians resolve electrical problem with Soyuz craft, NASA official says
News analysis by James Oberg NBC News space analyst
updated 5:49 a.m. PT, Tues., Oct. 21, 2008
During the previous two Soyuz descents from the international space station, in October 2007 and April 2008, the spacecraft suffered the same type of major anomaly when explosive bolts failed to separate the crew cabin cleanly from other no-longer-needed sections of the vehicle. As a result, in each case, the ship’s landing guidance system switched to a steering mode that dropped the crews far short of their aim points, and far higher accelerations.
With a little added bad luck, such a landing could have killed everybody on board. But for the past few months, Russian space officials have been assuring NASA and the public — as well as the three men who will be inside the descending Soyuz this week — that everything is now under control.Russian space officials say they solved the problem going forward by making modifications in the spacecraft, starting with the one that was launched this month and will remain attached to the space station until next spring. As for the Soyuz due to come back this week, the Russians say the problem was fixed when an explosive bolt was removed during an emergency spacewalk in July.
Of course, all this assumes that the problem has been correctly identified. And there's the rub.
The supposedly faulty bolt assembly has not yet even been returned to Earth for disassembly and inspection. It will be coming home on the current return mission, and could provide the first real evidence that the theory behind the previous failures (and the justification for the workarounds and repairs) is correct.
The opposing theory — that the proposed failure mode is wrong and that the cause is something else — could be proved as soon as Thursday night if a similar anomaly occurs. Russian cosmonauts Sergei Volkov and Oleg Kononenko, along with American video-game millionaire Richard Garriott, are due to land at 11:36 p.m. ET Thursday (which is midmorning on the following day in the Kazakh landing zone). NASA TV will carry the entire landing sequence live on the Internet.
It’s not hard to imagine scenarios even worse than the previous two hard landings. In some, the falling spacecraft becomes wrapped in flames before it has correctly aligned its heat shield frontward, leading to fiery penetration of its hull. In other scenarios, critical landing systems such as the parachutes are disabled by thermal stresses and fail to slow the ship for its final touchdown. Such possibilities should be answered with the kinds of solid reassurances that have been lacking. Until now.
A theory you can believe in
A more complete explanation behind the Russian theory came out this week from a NASA space official in Houston. The official requested that his name not be used because he was not authorized to divulge the information. His expertise is well-known, however, and he is highly trustworthy.
The explanation made more sense to me — and relieved a lot more anxiety — than all the public reassurances that have come out over the past six months.
According to this source, the anomalies were caused by a combination of electrical phenomena in space and some hardware features of the Soyuz. It is well-documented that the space station plows through a field of charged particles on the edge of the upper atmosphere as well as Earth’s own magnetic field.
The source said this “allowed a low-level current to flow through the pyro bolts over a long period of time.” The electrical current induced heating. Even in zero gravity, the bolt’s powder fused and shriveled away from the "flash wire" that is supposed to ignite it when commanded. As a result, when the command was issued, the powder did not ignite.
Under terrestrial conditions, he said, “the Russians did reproduce this phenomenon with a simulated environment and a ‘training bolt,’” but not with a flight-qualified bolt. That probably was close enough.
Coincidentally, the bolt that was susceptible to the electrical effect was the only one that spacewalking cosmonauts could access last summer using existing transfer equipment. By removing the bolt at that time, they guaranteed that it would not "hang up" even if it failed to fire this time. This hangup had twice jerked the modules into a brief uncontrolled tumble before they tore loose in the rising flames of re-entry and then, just in time, properly turned the heat shield into those flames.
Adding a flurry of fixes
There was not enough timely insight to add any sensors to the returning Soyuz, to tell the crew that the bolts have indeed fired correctly. However, the expected velocity changes from a nominal separation have been calculated, and the crew will be monitoring their own navigation system to report these changes — or their absence — within several seconds of the required time of separation, the source said. All subsequent Soyuz vehicles, including the one just launched, have thermal sensors on the bolts that will tell ground controllers whether or not the bolts have fired properly.
In addition, the Soyuz will have a software patch, not further described, “that will help the vehicle separate due to atmospheric heating if the pyro lock fails to open,” the source said. But as with any such fast fixes for complex applications, there is always some anxiety that the fix itself may introduce new failure modes.
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From here on out, the Soyuz craft will have better electrical grounding, sturdier explosive bolts and rerouted circuitry for the bolt-firing mechanism.
And just to make sure, a task has been added to a scheduled spacewalk in December to install instrumentation near the Soyuz parking ports, in order to measure the electrical environment more precisely. By then, the returned bolt will have been inspected and compared to the test bolt that was subjected to similar electrical effects in the laboratory.
If the theory is actually verified, this anomaly can be retired, joining a long list of "spaceflight funnies" that have bedeviled space missions for decades. And the Russian space teams can clear the decks for the next "funny" waiting out there. That these continue to occur is no surprise. The only really scary outcome is if they stop being solved.
Thursday night, we’ll get a new data point.
NBC News space analyst James Oberg spent 22 years at NASA's Johnson Space Center as a Mission Control operator and an orbital designer.
Chandrayaan-1 (Present Configuration)
|Organization||Indian Space Research Organisation|
|Launch date||22 October, 2008 from Sriharikota, India|
|Launch vehicle||PSLV-XL / PSLV-C11) (modified version of PSLV)|
|Mission duration||2 years|
|Mass||523 kilograms (1,153 lb)|
|Power||Solar (750 W)|
|Apoapsis||initial 7,500 km (4,660 mi), final 100 km (62 mi)|
|Periapsis||initial 500 km (311 mi), final 100 km (62 mi)|
Chandrayaan-1 (Sanskrit: चंद्रयान-1, lit: Lunar Craft-1), is an unmanned lunar exploration mission by the Indian Space Research Organisation (ISRO), India's national space agency. The mission includes a lunar orbiter as well as an impactor. The spacecraft was launched by a modified version of the Polar Satellite Launch Vehicle on 22 October 2008.
The remote sensing satellite weighs 1,308 kilograms (2,884 lb) (590 kilograms (1,301 lb) initial orbit mass and 504 kilograms (1,111 lb) dry mass) and carries high resolution remote sensing equipment for visible, near infrared, soft and hard X-ray frequencies. Over a two-year period, it is intended to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. The polar regions are of special interest, as they might contain water ice.
The spacecraft was successfully launched on 22 October 2008 at 6:22 am Indian Standard Time (00:52 UTC). After the spacecraft reaches its lunar transfer orbit, it will take 5.5 days to reach the Moon. They estimate the cost to be Rs. 3.86 billion (US$ 80 million).
- To launch and orbit a spacecraft in lunar polar orbit and conduct scientific studies.
- To carry out high resolution mapping of topographic features in 3D, distribution of various minerals and elemental chemical species including radioactive nuclides covering the entire lunar surface using a set of remote sensing payloads. The new set of data would help in unraveling mysteries about the origin and evolution of the Solar System in general and that of the Moon in particular, including its composition and mineralogy.
- Realise the mission goal of harnessing the science payloads, lunar craft and the launch vehicle with suitable ground support system including DSN station, integration and testing, launching and achieving lunar orbit of ~100 km, in-orbit operation of experiments, communication/telecommand, telemetry data reception, quick look data and archival for scientific utilisation by identified group of scientists.
- 1380 kg at launch, 675 kg at lunar orbit, and 523 kg after releasing the impactor.
- Cuboid in shape of approximately 1.5 m
- X band, 0.7 m diameter parabolic antenna for payload data transmission. The Telemetry, Tracking & Command (TTC) communication operates in S band frequency.
- The spacecraft is mainly powered by its solar array, which includes one solar panel covering a total area of 2.15 x 1.8 m2 generating 700W of power, which is stored in a 36 Ah Lithium-ion battery. The spacecraft uses a bipropellant integrated propulsion system to reach lunar orbit as well as orbit and attitude maintenance while orbiting the Moon.
Specific areas of study
- High-resolution mineralogical and chemical imaging of permanently shadowed north and south polar regions.
- Search for surface or sub-surface water-ice on the Moon, specially at lunar poles.
- Identification of chemical end members of lunar high land rocks.
- Chemical stratigraphy of lunar crust by remote sensing of central upland of large lunar craters, South Pole Aitken Region (SPAR) etc., where interior material may be expected.
- To map the height variation of the lunar surface features along the satellite track.
- Observation of X-ray spectrum greater than 10 keV and stereographic coverage of most of the Moon's surface with 5m resolution
- To provide new insights in understanding the Moon's origin and evolution.
The scientific payload has a total mass of 90 kg and contains six Indian instruments and six foreign instruments.
- The Terrain Mapping Camera (TMC) has 5 m resolution and a 40 km swath in the panchromatic band and will be used to produce a high-resolution map of the Moon.
- The Hyper Spectral Imager (HySI) will perform mineralogical mapping in the 400-900 nm band with a spectral resolution of 15 nm and a spatial resolution of 80 m.
- The Lunar Laser Ranging Instrument (LLRI) will determine the surface topography.
- An X-ray fluorescence spectrometer (C1XS) covering 1- 10 keV with a ground resolution of 25 km and a Solar X-ray Monitor (XSM) to detect solar flux in the 1–10 keV range. C1XS will be used to map the abundance of Mg, Al, Si, Ca, Ti, and Fe at the surface, and will monitor the solar flux. This payload is a collaboration between Rutherford Appleton laboratory, U.K, ESA and ISRO.
- A High Energy X-ray/gamma ray spectrometer (HEX) for 30- 200 keV measurements with ground resolution of 40 km, the HEX will measure U, Th, 210Pb, 222Rn degassing, and other radioactive elements
- Moon Impact probe (MIP) developed by the ISRO, is a small satellite that will be carried by Chandrayaan-1 and will be ejected once it reaches 100 km orbit around Moon, to impact on the Moon. MIP carries three more instruments, namely, a high resolution mass spectrometer, an S-Band altimeter and a video camera. The MIP also carries with it a picture of the Indian flag, its presence marking as only the fourth nation to place a flag on the Moon after Russia (however, Luna 2 carried the Soviet flag and coat of arms), United States and Japan.
- Among foreign payloads, The Sub-keV Atom Reflecting Analyser (SARA) from the ESA will map composition using low energy neutral atoms sputtered from the surface.
- The Moon Mineralogy Mapper (M3) from Brown University and JPL (funded by NASA) is an imaging spectrometer designed to map the surface mineral composition.
- A near infrared spectrometer (SIR-2) from ESA, built at the Max Planck Institute for Solar System Research, Polish Academy of Science and University of Bergen, will also map the mineral composition using an infrared grating spectrometer. The instrument will be similar to that of the Smart-1 SIR.
- S-band miniSAR, designed, built and tested for NASA by a large team that includes the Naval Air Warfare Center, Johns Hopkins University Applied Physics Laboratory, Sandia National Laboratories, Raytheon and Northrop Grumman; it is the active SAR system to search for lunar polar ice. The instrument will transmit right polarized radiation with a frequency of 2.5 GHz and will monitor the scattered left and right polarised radiation. The Fresnel reflectivity and the circular polarisation ratio (CPR) are the key parameters deduced from these measurements. Ice shows the Coherent Backscatter Opposition Effect which results in an enhancement of reflections and CPR, so that water content of the Moon polar region can be estimated.
- Radiation Dose Monitor (RADOM-7) from Bulgaria is to map the radiation environment around the Moon.
Launch took place 22 October 2008 at 6.22 am IST from Satish Dhawan Space Centre using ISRO's PSLV launch rocket. The rocket 44.4 metre tall four-stage rocket is supposed to launch the spacecraft into orbit. Chandrayaan will take 15 days to reach the lunar orbit. ISRO's telemetry, tracking and command network (ISTRAC) at Peenya in Bangalore, will be tracking and controlling Chandrayaan-1 over the next two years of its life span.
Since its perfect launch, Chandrayaan has performed several engine burns, moving it into the designated Geostationary transfer orbit (GTO) around earth and has successfully communicated with base center.
Once in GTO, Chandrayaan's on-board motor will be fired to take it to the lunar orbit with 1,019 km perigee and 386,194 km apogee from the Earth around November 8. This orbit will take the spacecraft to the vicinity of the moon.
The spacecraft will rotate for about five-and-a-half days before firing the engine to slow its velocity for moon's gravity to capture it. As the spacecraft approaches the moon, its speed will be reduced to enable the gravity of the moon to capture it into an elliptical orbit. A series of engine burns will then lower its orbit to its intended 100 km circular polar orbit. Following this, the Moon Impact Probe (MIP) will be ejected from Chandrayaan-1 and all the scientific instruments/payloads are commissioned.
|Organization||Indian Space Research Organization|
|Mission type||Orbiter, Rover|
|Mission duration||1 month (rover)|
|Mass||30 to 100 kg (rover)|
The ISRO is also planning a second version of Chandrayaan named: Chandrayaan II. According to ISRO Chairman G. Madhavan Nair, "The Indian Space Research Organisation (ISRO) hopes to land a motorised rover on the Moon in 2010 or 2011, as a part of its second Chandrayaan mission. The rover will be designed to move on wheels on the lunar surface, pick up samples of soil or rocks, do in situ chemical analysis and send the data to the mother-spacecraft Chandrayaan II, which will be orbiting above. Chandrayaan II will transmit the data to Earth."
Chandrayaan II will consist of the spacecraft itself and a landing platform with the Moon rover. The platform with the rover will detach from the orbiter after the spacecraft reaches its orbit above the Moon, and land on lunar soil. Then the rover will roll out of the platform. Mylswamy Annadurai, Project Director, Chandrayaan I, said: "Chandrayaan II will carry a semi-hard or soft-landing system. A motorised rover will be released on the Moon's surface from the lander. The location for the lander will be identified using Chandrayaan I data."
The rover will weigh between 30 kg and 100 kg, depending on whether it is to do a semi-hard landing or soft landing. The rover will have an operating life-span of one month. It will run predominantly on solar power.
NASA Lunar Outpost
According to Ben Bussey, senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, Chandrayaan's imagery will be used to decide the future Lunar outpost that NASA has recently announced. Bussey told SPACE.com, "India's Chandrayaan-1 lunar orbiter has a good shot at further identifying possible water ice-laden spots with a US-provided low-power imaging radar." Bussey advised - one of two US experiments on the Indian Moon probe. "The idea is that we find regions of interest with Chandrayaan-1 radar. We would investigate those using all the capabilities of the radar on NASA's Lunar Reconnaissance Orbiter", Bussey added, "a Moon probe to be launched late in 2008." (The LRO is now scheduled for launch 24 April 2009).
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- ^ "Chandrayaan-I Launch was Nominal".
- ^ [BBC
- ^ a b "Speifications of Chandrayaan 1". Indian Space Research Organisation (October 2008). Retrieved on 2008-10-22.
- ^ "FAQ on Chandrayaan 1". Indian Space Research Organisation (October 2008). Retrieved on 2008-10-22.
- ^ A. S. Kiran Kumar, A. Roy Chowdhury (2005). "Terrain mapping camera for Chandrayaan-1" (PDF). J. Earth Syst. Sci. 114 (6): 717–720. doi:10.1007/BF02715955.
- ^ "The Chandrayaan-1 X-ray Spectrometer: C1XS". Rutherford Appleton Laboratory. Retrieved on 2008-10-21.
- ^ "Indian flag to be only fourth on Moon". domain-b.com.
- ^ Bhardwaj, A., S. Barabash, Y. Futaana, Y. Kazama, K. Asamura, D. McCann, R. Sridharan, M. Holmström, P. Wurz, R. Lundin (2005). "Low energy neutral atom imaging on the Moon with the SARA instrument aboard Chandrayaan-1 Mission" (PDF). J. Earth System Sci 114 (6): 749–760. doi:10.1007/BF02715960.
- ^ Basilevsky A. T., Keller H. U., Nathues A., Mall J., Hiesinger H., Rosiek M. (2004). "Scientific objectives and selection of targets for the SMART-1 Infrared Spectrometer (SIR)". Planetary and Space Science 52: 1261–1285. doi:10.1016/j.pss.2004.09.002.
- ^ P. D. Spudis, B. Bussey, C. Lichtenberg, B. Marinelli, S. Nozette (2005). "mini-SAR: An Imaging Radar for the Chandrayaan 1 Mission to the Moon". Lunar and Planetary Science 26.
- ^ "Chandrayaan-I successfully put into earth's orbit", Indian express (Oct 22, 2008). Retrieved on 2008-10-22.
- ^ a b "India launches first Moon mission", BBC (22 October 2008). Retrieved on 2008-10-22.
- ^ "Chandrayaan-1 launched", Sriharikota, Andhra Pradesh, IBN Live (Oct 22, 2008). Retrieved on 2008-10-22.
- ^ "India, Russia to expand n-cooperation, defer Kudankulam deal". Earthtimes.org.
- ^ Moonbase: In the Dark On Lunar Ice | Space.com | 26 December 2006
B. H. Foing (2004). "The case for the first Indian robotic mission to the Moon". Current Science 87: 1061–1065.
- Official Homepage of Chandrayaan-1
- Chandrayaan-1 Mission Profile by NASA's Solar System Exploration
- Chandrayaan-1 Announcement of Opportunity and home page from ISRO
- Chandrayaan Animation by Thejes on YouTube
- High Resolution version of the Chandrayaan Animation by Thejes
- European Space Agency to cooperate with India's first lunar mission
- NSSDC Chandrayaan-1 page
- M3 fact sheet
- SPACE.com: U.S. radar on Chandrayaan-1?
- The case for Chandrayaan
- C1XS X-ray Spectrometer Instrument
- Link to C1XS/Chandrayaan-1 Animation produced by Doug Ellison
Technology & science: Space