First Dutch detector array ready for Gusto mission

Jessica Vermeer

https://bits-chips.nl/artikel/first-dutch-detector-array-ready-for-gusto-mission/

The first detector array for NASA’s Gusto mission has passed pre-shipment review, reports the Netherlands Institute for Space Research (SRON). The array is being shipped to the University of Arizona, where it will be integrated into the balloon observatory. The Gusto mission is to measure emissions from cosmic material between stars. SRON and Delft University of Technology are developing three 8-pixel arrays for 4.7, 1.9 and 1.4 THz. The team has now delivered its first array — for the 4.7 THz channel.

NASA’s Galactic/extragalactic ULDB Spectroscopic Terahertz Observatory (Gusto) is a balloon observatory that will drift in Earth’s atmosphere for over 75 days, at the edge of space at 36 km altitude. The launch is scheduled for December 2021 from Antarctica. The observatory consists of a telescope of one meter in diameter and three observation instruments carried by an ultra-long duration balloon (ULDB). It contains three array receivers for electromagnetic radiation of 1.4, 1.9 and 4.7 THz.

Delivering the first array is the result of an international collaboration involving SRON, TU Delft, the University of Arizona and NASA. The 4.7 THz channel is the most challenging to realize because it requires the highest sensitivity and most precise pointing of the lens-antenna beam. The design, manufacturing, assembly and testing of the array were carried out at SRON, while the superconducting detectors were developed at TU Delft.

The first 4.7 THz detector array for the Gusto mission. Every sphere represents one pixel. All spheres combined form an 8-pixel array. Credit: SRON

Gusto has three channels to map respectively ionized nitrogen (NI), carbon (CII), and oxygen (OI) emission lines in the spectrum of the interstellar medium — the material floating in between stars. This helps scientists to determine the life cycle of interstellar gas in our Milky Way, witness the formation and destruction of star-forming clouds and understand the dynamics and gas flow in the vicinity of the center of our Galaxy.

Abstract-4×2 HEB receiver at 4.7 THz for GUSTO

J. R. G. Silva; B. Mirzaei; W. Laauwen; N. More; A. Young; C. Kulesa; C. Walker; A. Khalatpour; Q. Hu; C. Groppi; J. R. Gao

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10708/107080Z/42-HEB-receiver-at-47-THz-for-GUSTO/10.1117/12.2313410.short

GUSTO will be a NASA balloon borne terahertz observatory to be launched from Antarctica in late 2021 for a flight duration of 100-170 days. It aims at reviewing the life cycle of interstellar medium of our galaxy by simultaneously mapping the three brightest interstellar cooling lines: [OI] at 4.7 THz, [CII] at 1.9 THz, and [NII] at 1.4 THz; along the 124 degrees of the galactic plane and through a part of the Large Magellanic Cloud. It will use three arrays of 4x2 mixers based on NbN hot electron bolometers (HEBs), which are currently the most sensitive mixers for high resolution spectroscopic astronomy at these frequencies.

Here we report on the design of a novel 4.7 THz receiver for GUSTO. The receiver consists mainly of two subsystems: a 4×2 HEB quasi-optical mixer array and a 4.7 THz multi-beam LO. We describe the mixer array, which is designed as a compact monolithic unit. We show, for example, 10 potential HEB detectors with the state of the art sensitivity of 720 K measured at 2.5 THz. They have a small variation in sensitivity, being less than 3%, while also meet the LO uniformity requirements. For the multi-beam LO we demonstrate the combination of a phase grating and a single QCL at 4.7 THz, which generates 8 sub-LO beams, where the phase grating shows an efficiency of 75%. A preliminary concept for the integrated LO unit, including QCL, phase grating and beam matching optics is presented.

NASA chooses Dutch terahertz detectors

Out of 32 proposals, NASA decided on the GUSTO mission as the project of choice to launch in December 2021. The terahertz sensors aboard the balloon-launched mission will be made in the Netherlands.

http://delta.tudelft.nl/artikel/nasa-chooses-dutch-terahertz-detectors/32957

NASA wants to untangle the complexities of the dust in between stars, as photographed here by the Hubble Space Telescope.

Dr. Jian Rong Gao was excited by the NASA press release last Friday. It says that the Gusto mission was selected as the mission to be built in the next few years.

'NASA has determined that Gusto (Galactic/extragalactic ULDB spectroscopic terahertz observatory) has the best potential for excellent science return with a feasible development plan,' says the press release.

The terahertz sensors on the mission will be made at Gao's lab at the section quantum nanoscience from the TU Delft Faculty of Applied Sciences (TNW) in collaboration with the Dutch organisation for space research SRON.

The sensors have been tried and tested in the STO2 mission (Stratospheric Terahertz Observatory) that was launched shortly before Christmas last year. The sensors are tuned to 1.4, 1.9 and 4.7 THz respectively to observe the presence of nitrogen, carbon and oxygen.

The 2021 mission will feature three eight-pixel cameras and other equipment necessary for the ultra-sensitive detection of terahertz radiation from the cosmic material between the stars. Dr. Christopher Walker of the University of Arizona will be the principal investigator on the project.

NASA says it has selected a science mission that will measure emissions from the interstellar medium. This data will help scientists determine the life cycle of interstellar gas in our Milky Way galaxy, witness the formation and destruction of star-forming clouds, and understand the dynamics and gas flow in the vicinity of the centre of our galaxy.

NASA selects mission to study the chaotic "interstellar medium"

By Cage Appleby
https://www.neowin.net/news/nasa-selects-mission-to-study-the-chaotic-interstellar-medium

Galaxies, aliens, black holes and the stars are all well pondered and thought provoking subjects that garner a lot of attention when someone starts a narrative on space. Whether conversations of the latter begin on any sort of euphoric bender is irrelevant. Space is awesome and capable of imposing wonder upon almost anyone.

While space, for the most part, is a cold and isolated place devoid of matter, it does contain lonely dust and gas particles that drift between stars, a material known as the interstellar medium - who would have thought?

NASA has selected the Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) mission to conduct the first study of this chaotic matter, to further understand how it behaves.

Floating particles of gas and dust may sound like a trivial thing to study, and perhaps to most, it may even seem a little mundane. However, the interstellar medium is no trivial matter. It accounts for around 15% of the total mass in the Milk Way galaxy, with 99 percent of that being free floating rogue gasses like helium and hydrogen.

The whopping $40 million GUSTO mission will be led by University of Arizona professor of astronomy, Christopher Walker. If being a human floating on a moving and rotating imperfect sphere wasn't enough to make you feel like a cosmic minority, according to Walker, "4.7 billion years ago, every atom in your body was floating in the interstellar medium".

The mission is expected to kick-off with the launch of an Ultralong-Duration Balloon carrying a $40 million dollar telescope over Antarctica in 2021. The impressive telescope is capable of detecting oxygen, carbon, and nitrogen spectral emissions. These are frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.

While all this space jargon may be a little confusing, Paul Hertz, astrophysics division director in the Science Mission Directorate in Washington thankfully simplified GUSTO's mission plan below:

GUSTO will provide the first complete study of all phases of the stellar life cycle, from the formation of molecular clouds, through star birth and evolution, to the formation of gas clouds and the re-initiation of the cycle,”.

As stated above, if all goes as planned, the mission, or 'balloon', will take flight in December 2021 from the McMurdo Station in Antarctica.