OrbitalHub

Credits: NASA/ESA

The Hubble Space Telescope (HST) is a joint creation of NASA, ESA, hundreds of industrial companies, government and university groups, and thousands of engineers and scientists. Since April 1990, when it was released into orbit from Discovery’s payload bay, Hubble has returned scientific data and stunning images of stars, nebulae, and distant galaxies.

The construction of the space telescope began in the 1980s, when the optics company Perkin-Elmer initiated the work on Hubble’s primary light-collecting mirror. The Hubble Space Telescope was completed in 1985, but was not deployed in Earth’s orbit for another five years.

In 1983, the Space Telescope Science Institute (STScI) was founded and it assumed from NASA the science management of the Hubble Space Telescope. STScI is located at Johns Hopkins University.

In its initial configuration, Hubble carried the Wide Field and Planetary Camera (WF/PC), the Goddard High Resolution Spectrograph (GHRS), the Faint Object Camera (FOC), and the Faint Object Spectrograph (FOS). It was soon to be discovered that the primary mirror had a flaw, and that the space telescope suffered from blurry vision.

The Hubble Servicing Mission 1 installed a corrective optics package, COSTAR, and replaced the original WF/PC with the Wide Field and Planetary Camera 2. Hubble Servicing Mission 2 replaced the GHRS and FOS with the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Servicing Mission 3A replaced all six gyroscopes, a Fine Guidance Sensor, and the onboard computer. Servicing Mission 3B saw the installation of the Advanced Camera for Surveys (ACS), which replaced the FOC, and the revival of NICMOS through the installation of a new cooling system.

All this, and the history of astronomic discoveries beginning with Galileo Galilei in 1609 and continued by William Herschel, William Huggins, George Ellery Hale, and Edwin Hubble, are presented in Hubble – Imaging Space And Time, a book authored by David DeVorkin and Robert W. Smith. The book is replete with spectacular images captured by the Hubble Space Telescope. Images of Carina Nebula, Eagle Nebula, Orion Nebula, and Swan Nebula, just to name a few, are a celebration of color and convey the majestic beauty of the Cosmos.

David DeVorkin is curator of the history of astronomy and the space sciences at the National Air and Space Museum, Smithsonian Institution. Among other books he has authored are Beyond Earth: Mapping the Universe and The Hubble Space Telescope: Imaging the Universe.

Robert W. Smith is a professor of history and Director of the Science, Technology and Society Program at the University of Alberta. He is also the author of The Space Telescope: A Study of NASA, Science, Technology and Politics, The Hubble Space Telescope: Imaging the Universe, and The Expanding Universe.

Credits: NASA

STS-125 Space Shuttle Atlantis was the final Hubble Space Telescope servicing mission (SM4). The STS-125 crew consisted of Gregory C. Johnson, pilot; Scott D. Altman, commander; Michael J. Massimino, Michael T. Good, K. Megan McArthur, John M. Grunsfeld, and Andrew J. Feustel, all mission specialists.

STS-125 has some history behind it. In 2004, NASA head Sean O’Keefe cancelled the long-planned Hubble Space Telescope Servicing Mission 4, invoking new safety rules that were applied to space shuttle flights after the Columbia disaster. By June 2004, NASA was considering a robotic servicing mission, which was also cancelled due to prohibitive costs. A change in NASA policy came with the new head of NASA, Michael Griffin. The risks associated with the SM4 mission were reassessed, and by 2008 SM4 was back on track.

On May 11, 2009, STS-125 Space Shuttle Atlantis launched at 2:01 PM EDT. There were no obvious debris events during launch and after going through the post-launch checklist, the crew prepared the orbiter for in-orbit operations and conducted a survey of the payload bay and the crew cabin using the robotic arm.

On May 13, 2009, at 17:14 UTC, flight day #3, Hubble Space Telescope was grappled and by 18:12 UTC, the telescope was berthed in the payload bay of Atlantis.

There were a total of five EVAs performed by the STS-125 crew. During EVA#1 (John Grunsfeld/ Andrew Feustel), the Wide Field and Planetary Camera 2 (WFPC2) was replaced with the new Wide Field Camera 3 (WFC3), and the Science Instrument Command and Data Handling Unit were replaced. A Soft Capture Mechanism (SCM) was also installed on Hubble. SCM will be used to capture and de-orbit Hubble at the end of its operational life. EVA#2 (Michael Massimino/ Michael Good) replaced all three gyroscope rate sensing units (RSUs) and one of the battery unit modules. EVA#3 (John Grunsfeld/ Andrew Feustel) removed and replaced COSTAR with the Cosmic Origins Spectrograph, and replaced faulty electronics cards from the Advanced Camera for Surveys. EVA#4 (Michael Massimino/ Michael Good) removed and replaced electronics cards for the Space Telescope Imaging Spectrograph (STIS). EVA#5 (John Grunsfeld/ Andrew Feustel) replaced the second battery unit module, installed the Fine Guidance Sensor #3, replaced degraded insulation panels with New Outer Blanket Layer (NOBL)s, and also replaced a protective cover around Hubble’s low-gain antenna.

Hubble was released on May 19, 2009 (flight day #9). The telescope was lifted out of the orbiter’s payload bay using the robotic arm. After running through the release checklist, the STS-125 crew released Hubble at 12:57 UTC. The new equipment and the upgrades installed on Hubble will be tested for several months before resuming operation in early September.

Due to weather, which was less than favorable for landing, STS-125 had to delay the return to Earth for two days. The de-orbit burn was initiated on May 24, 2009, at 14:24 UTC.

STS-125 Space Shuttle Atlantis landed at Edwards Air Force Base in California, on Sunday May 24, 2009, at 11:39 AM EDT.

Credits: SETI Institute

SETI stands for Search for Extraterrestrial Intelligence. Initially a program supported by NASA, SETI is now a privately funded institute that conducts research activities to detect intelligent extraterrestrial life.

SETI Institute is currently collaborating with the Radio Astronomy Laboratory at UC Berkley to develop the Allen Telescope Array, which is a specialized radio telescope array designed for SETI studies.

Seth Shostak, senior astronomer at the SETI Institute, kindly answered a few questions related to the search for extraterrestrial intelligence.

DJ: Why did you choose to work for SETI?
Seth Shostak: It probably sounds too easy, and thoroughly trite, but I’ve been interested in the idea of extraterrestrial intelligence since I was ten years old. When, quite by chance, the opportunity arose to work for the SETI Institute, it was like finding that a dream was suddenly reality.

DJ: Besides listening for transmissions in the microwave range of radio frequencies, which methods do you think are most likely to prove successful for SETI?
S.Shostak: I happen to be a big fan of so-called Optical SETI, as well as traditional radio SETI. In other words, look for laser flashes that might be sent our way by extraterrestrial societies trying to get in touch. This would be a great way to initiate contact, as the transmitting civilization could “ping” many thousands — indeed, many millions — of star systems in short order, and then do it again. This would be a sort of endless ping to so many star systems that it might reliably generate some reaction. In any case, I think we need to expand our search for these quick flashes in the sky.

DJ: Is SETI looking only for carbon-based ET? Are there any other possibilities to consider when searching for extraterrestrial intelligence?
S.Shostak: SETI searches are agnostic when it comes to the biochemistry of the aliens. After all, from our point of view, what makes them “intelligent” is their ability to build a radio transmitter or a powerful laser. The details of their construction are of no consequence for the search — except insofar as they might not be living on planets surrounding an ordinary star. If they are machine intelligence, they may have migrated away from their natal solar system, and of course that WOULD affect our search strategies.

DJ: Do new discoveries made by astronomers using space telescopes (for example, discovery of exo-planets, detection of their atmospheres, and the study of the composition of these atmospheres using spectral lines, etc.) have any implications for the way SETI conducts searches? Is SETI using this information to fine-tune the search?
S.Shostak: One of the first SETI experiments planned for the Allen Telescope Array is to examine star systems that are known to have planets (the work of astronomers during the past dozen years). Of course, we would like to know which star systems have HABITABLE planets, but that information still eludes us. NASA’s Kepler Mission will give us invaluable insight into what fraction of the cosmos might be suitable for life — and life of the intelligent variety, as well.

DJ: How do you see a two-way communication with ET? What concepts can be considered universal so that they can be used for such communication?
S.Shostak: Given the likely distance between societies, I don’t think that two-way communication is very likely or practical. But there’s still the problem that any deliberate transmissions should be encoded in such a way that the recipients can figure out what is being said. Lots of thought has gone into this problem — should the aliens send dictionaries, mathematics, music, or just a lot of pictures? In general, I figure that the more information they send, the greater the chance that we’ll understand at least some of it.

DJ: Can you make a prediction as to when an ET radio transmission could be picked up by terrestrial receivers? Besides the pace at which terrestrial technology is evolving, what other factors should be considered when making such a prediction?
S.Shostak: The most important parameter affecting SETI success these days is money: do we have sufficient funds to keep up the search? But if the money is forthcoming, then technical developments in the coming decades will allow us to examine a million or more star systems by 2025 or so. I think a million star systems is the right number to expect success, so that’s my prediction — we’ll find ET by 2025. Otherwise, I’ll be disappointed and slightly embarassed.

Seth Shostak’s new book, Confessions of An Alien Hunter: A Scientist’s Search for Extraterrestrial Intelligence, tells the true story of SETI. The book contains answers to many questions about SETI: what frequencies are monitored, where the antennas are aimed, how we should respond if a signal is received, etc. By reading this book, I have learned a great deal about the search for extraterrestrial intelligence.

Paul Gilster of Centauri Dreams has posted a review of the book. I invite everyone to read it.

Credits: NASA/MSFC

Delta II is a space launch system operated by United Launch Alliance (ULA), which was initially built by McDonnell Douglas, and by Boeing Integrated Defense Systems after McDonnell Douglas merged with Boeing in 1997.

As any other early space launch system, it evolved from a ballistic missile. In the 1960s, the Thor intermediate-range ballistic missile was modified to become the Delta launch vehicle. In 1981, after being operated for 24 years, Delta production was halted due to a change in U.S. space policy. However, in 1986, after the Challenger accident, it was decided that the Space Shuttle fleet would not carry commercial payloads anymore, paving the way for the return of the Delta launch vehicle. Delta II had its maiden flight on February 14, 1989.

Delta II launch vehicle is 38.2 to 39 m long, with a diameter of 2.44 m, and a mass that can range from 151,700 to 231,870 kg, depending on configuration. Delta II can be configured with two or three stages.

Delta II can inject a payload having a mass of 2,700 to 6,100 kg in low Earth orbit (LEO). Payloads deployed to Geosynchronous Transfer Orbit (GTO) can have a mass from 900 to 2,170 kg.

The first stage, Thor/Delta XLT-C, is powered by one Pratt & Whitney Rocketdyne RS-27A liquid fuel engine. The RS-27A engine is fueled by RP-1 and liquid oxygen. The RS-27A engine provides around 1,000 kN of thrust.

Credits: NASA

The solid boosters are used to increase the thrust of the launch vehicle. The first solid boosters used by Delta II 6000 series were Castor 4A motors. The 7000 and 7000 Heavy series use GEM 40 and GEM 46 solid motors respectively. The increase in thrust from Castor 4A to GEM 46 is substantial, from 480 kN to 630 kN.

Stage two, Delta K, is powered by a hypergolic restartable Aerojet AJ10-118K engine that can provide 43 kN. The AJ10-118K can fire more than once in order to insert the payload into LEO. The engine uses dinitrogen tetroxide as oxidizer and aerozine 50 (which is a mix of hydrazine and unsymmetrical dimethylhydrazine) as fuel. Besides having hard to pronounce names, the oxidizer and the fuel are very toxic and corrosive. The second stage contains the flight control system, which is a combined inertial system and guidance system.

The third stage, if present in the configuration, is a Payload Assist Module (PAM). This stage is powered by an ATK-Thiokol motor, which provides the velocity change needed for missions beyond Earth orbit. The stage has no active guidance control and it is spin-stabilized.

The de-spin mechanism used to slow the spin of the spacecraft after the burn and before the stage separation is a yo-yo de-spin mechanism. This mechanism consists of two cables with weights on the ends. The weights are released and the angular momentum transferred from the stage reduces the spin to a value that can be controlled by the attitude control system of the spacecraft.

Delta II can launch single, dual, or multiple payloads during the same mission. There are three fairing sizes available: composite 3-meter diameter, aluminum 2.9-meter diameter, and stretched composite 3-meter diameter.

Credits: NASA

Delta II is assembled on the launch pad. After hoisting the first stage into position, the solid boosters are hoisted and mated with the first stage. The second stage is then hoisted atop the first stage.

Delta II launch vehicles have a four-digit naming system. The first digit can be either 6 or 7, designating the 6000 or 7000 series. The second digit indicates the number of solid boosters used for the mission. Delta II can have three, four, or nine solid boosters strapped to the first stage. The third digit denotes the engine type used for the second stage. This digit is two for 6000 and 7000 series Delta II, which indicates the Aerojet A10 engine. The last digit designates the type of the third stage. Zero means that no third stage is used, whereas five indicates a third stage powered by a Star 48B solid motor, and 6 marks a third stage powered by a Star 37FM motor. A Delta II 7426 has 4 solid boosters and a third stage powered by a Star 37FM motor.

Delta II proved to be a very reliable Expendable Launch Vehicle (ELV). Some NASA missions that used Delta II as launch vehicle include: Mars Global Surveyor, Mars Pathfinder, Mars Exploration Rovers (MER-A Spirit and MER-B Opportunity), Mars Phoenix Lander, Dawn, STEREO, and Kepler.

After long years of service, Delta II is getting close to retirement. The final mission for Delta II is currently scheduled for 2011.

You can find more information about the Delta launch vehicles on the Delta web page on Boeing’s web site.

Credits: NASA/Northrop Grumman

The launch date for the Lunar CRater Observation and Sensing Satellite (LCROSS), initially set for April 24, 2009, was pushed to June 2, 2009.

Dr. Anthony Colaprete, a planetary scientist at NASA Ames Research Center and the principal investigator for the LCROSS mission, gave a lecture as part of the Silicon Valley Astronomy Lecture series. The lecture was posted on NASA’s website as Prospecting for Water on the Moon: The Upcoming LCROSS Mission.

If you are an amateur astronomer and have a telescope, you can contribute to the LCROSS mission by participating in the LCROSS Observation Campaign. Images provided by the public will be a valuable addition to the mission archive.

Please stay tuned on OrbitalHub for more details about the LCROSS mission.

Credits: NASA/JPL

The Nuclear Spectroscopic Telescope Array (NuSTAR) is a high-energy X-ray space telescope that will expand our understanding of the origins and the development of stars and galaxies.

NuSTAR was proposed to NASA in May 2003. In 2006, while NuSTAR was undergoing an extended feasibility study, NASA cancelled the program due to budgetary constraints. However, in September 2007, the program was restarted.

In 2007, Orbital Sciences Corporation was selected by NASA to design, manufacture, and test the NuSTAR telescope.

The spacecraft is based on a proven design, used by Orbital for other NASA Small Explorer missions: SORGE, GALEX, AIM, and OCO. NuSTAR will have a launch mass of 360 kg, and will be powered by articulated solar arrays providing 600 W.

The spacecraft incorporates a ten-meter long extendable mast. The mast allows the telescope to fit into a small launch vehicle.

The technology used to build the telescope is not new. A team of researchers, led by Dr. Fiona Harrison, professor of physics and astronomy at Caltech, has been improving the NuSTAR technology for the last ten years. A previous high energy X-ray telescope (High Energy Focusing Telescope or HEFT) was developed as part of a high altitude balloon payload.

The currently operational X-ray telescopes, Chandra and XMM-Newton, observe the sky in the low energy X-ray spectrum (X-ray energies less than 10 keV). NuSTAR will make observations in a higher range, up to 79 keV. As much of the energy emitted by a black hole is absorbed by the surrounding gas and dust, observations in the high-energy X-ray spectrum can reveal in greater detail what is happening closer to the event horizon.

Credit: NASA/CXC/CfA/R.Kraft et al./MPIfR/ESO/APEX/A.Weiss et al./ESO/WFI

The NuSTAR telescope will have a sensitivity two orders of magnitude greater than any other instrument used to detect black holes. NuSTAR will help scientists understand how black holes are distributed throughout the universe, and what powers the most active galaxies.

The NuSTAR instrument consists of two co-aligned hard X-ray telescopes. The ten-meter mast mentioned above separates the mirrors and the imaging detectors. The detectors are Cadmium Zinc Telluride (CdZnTe) detectors and do not require cryogenic operation.

On February 9, 2009, NASA awarded Orbital the launch services contract for the NuSTAR mission. The telescope will be launched in 2011 aboard a Pegasus XL launch vehicle. Pegasus XL will be carried beneath a L-1011 aircraft and released over the Pacific Ocean. The air-launch system is very cost-effective, providing flexibility during operation and requiring minimal ground support.

NuSTAR will be deployed into a 525×525 km low Earth orbit (LEO) with a twenty-seven degree inclination.

For more details about the science of NuSTAR, you can visit the mission’s home page at Caltech. Orbital has also posted a NuSTAR fact sheet on their web site.