On Dec. 15 this year, a team of Hopkins scientists will send a rocket on a 400 second journey from the historic White Sands Missile Range in New Mexico through earth’s atmosphere and beyond.
Upon reaching a target elevation of approximately 100 km above the earth’s surface and just outside its atmosphere, the rocket’s payload, a state-of-the-art spectro-telescope by the name of Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (or FORTIS, for short), will be exposed to the vacuum of space.
Then, in a mere 30 seconds, rocket’s telemetry system will analyze the telescope’s initial view of the stars, determine its exact location and orientation, and reorient itself to get a view of its target: a relatively nearby galaxy by the name of NGC 1365.
Upon locking in on its target, the telescope’s most novel instrument — an array of just over 8,000 microshutters — will be activated, allowing the telescope’s detectors to focus and constantly refocus on the brightest stars visible in the target galaxy, while blocking out background radiation.
After the data is collected, and the 30 seconds are up, the telescope will begin its descent back down to earth and eventually be collected by the team.
Led by Stephan McCandliss, research scientist in Hopkins University’s Department of Physics and Astronomy, FORTIS is the most recent project to be launched by Hopkins’ Sounding Rocket Program. The program focuses on the design of payloads to be sent into space by sounding rockets, which are relatively small sub-orbital launch vehicles specifically meant to carry scientific instruments into space for small periods of time and to aid in the study of deep space objects.
While the rockets themselves can only be used for a single launch, they hold great merit in the fact that they are immensely cost-effective when compared to traditional rockets used to put satellites into orbit. Therefore, they can efficiently provide scientists with a means for data collection outside of earth’s atmosphere.
FORTIS’s specific scientific goal is to take advantage of this type of flight to analyze ultraviolet radiation emitted by hydrogen, as detected from the stars in NGC 1365, and to produce spectrographic analysis of the galaxy.
The performance of this detection outside of earth’s atmosphere is needed because the detection of ultraviolet radiation is amplified in the vacuum of space, where neither pressure nor gases in the atmosphere itself can hinder the detectors. By analyzing the spectra of NGC 1365, the project hopes to provide insight to a variety of issues surrounding Lyman alpha radiation in space.
In performing the analysis alone, the project will make a major contribution to the field of spectroscopy, which focuses on the analysis of radiation and its origins. The telescope will be one of the first to test out a new prototype being developed by NASA: the microshutter array. It is a small cell of 128 x 64 “shutters,” which can be individually opened and closed by the application and removal of a magnetic field. Each shutter is only 100 x 200 microns in size.
Whereas traditional spectroscopy allows for the analysis of radiation by dispersing it as it passes through thin slits and detecting the dispersion, microshutter arrays that use spectroscopy will allow for the same type of spectral dispersion and detection with multiple radiation sources at a time.
Additionally, it holds the unique advantage of dynamically adjustment of variable numbers of radiation sources and blocking out background radiation. This is useful when analyzing multiple objects at once with a high degree of precision. The implications of this are that it may be applicable to fields beyond astronomy, perhaps in biotechnology, medicine, and communications as well.
Although the project was first conceived by McCandliss in 2004, work didn’t officially begin until about six years ago. In that time, McCandliss needed to determine mission requirements, design the sounding rocket, acquire or fabricate the technology that would be utilized in the telescope, and calibrate the entire system.
All of this will be followed up with a sequence testing launch by the group at the Wallops Flight Facility in Virginia. This is to check their system’s setup for the actual launches in December. Should the telescope not pass sequence testing in October, the team hopes for a re-testing soon after and has identified a window of time next January during which the earth will still be at the proper location in the solar system for the telescope to view NGC 1365.
As much as it is an achievement in science, the Sounding Rocket Program at Hopkins serves as a terrific example of Hopkins’ excellent inclusion of students in research at the forefronts of their fields. “[The program] has a long history, kind of like a guild,” McCandliss said.
New students are continuously recruited. “[Knowledge about the projects is passed] along by oral tradition,” McCandliss said. The students on the project for FORTIS were trained from the ground up, having to learn about mechanics, electronics, computer programming, optics, and astronomy in general.
In time, however, the results were rewarding. “[I enjoy the] self containedness of the project,” Keith Redwine, a graduate student helping with the project, said. He described it to be quite hands on and found himself to be much more useful after learning all that he did within the project.
Seeing that the Sounding Rocket Program serves as an excellent opportunity to gain experience and learn, Redwine encourages students to apply to the program if interested.
