BLITS (Ball Lens In The Space)
BLITS is a retroreflector demonstration nanosatellite, a geodetic sphere, which was designed and manufactured by the FSUE-IPIE (Federal State Unitary Enterprise - Institute for Precision Engineering) R&D center (Moscow, Russia), under a 2006 agreement between Roskosmos and ILRS (International Laser Ranging Service). The purpose of the mission is experimental verification of the spherical glass retroreflector (low-refraction index glass, LK6 type) satellite concept. 1) 2)
The BLITS retroreflector has a heritage of a small spherical retroreflector of the same type (6 cm in diameter) which was flown on the Meteor-3M spacecraft (launch Dec. 10, 2001) and tested during the timeframe 2001-2006 by the ILRS (International Laser Ranging Service). 3)
Note: The FSUE-IPIE research institute is referred to in Russian as NIIPP (NII Pretsizionnogo Priborostroeniya).
Figure 1: Illustration of the BLITS nanosatellite (image credit: IPIE, NASA)
BLITS is a passive nanosatellite, consisting of two outer hemispheres made of a low-refraction-index glass (LK6 type) and an inner ball lens made of a high-refraction-index glass (TF105 type). The ball lens radius is 53.52 mm, the total radius of the spherical retroreflector is 85.16 mm. The hemispheres are glued over the ball lens; the external surface of one hemisphere is covered with an aluminum coating protected by a varnish layer. All spherical surfaces are concentric.
The nanosatellite is being used for precise SLR (Satellite Laser Ranging) measurements from the ILRS ground station network. The BLITS retroreflector should have zero ‘signature’ and thus represent the most accurate geodetic satellite currently in orbit. 4)
The nanosatellite has an outer diameter of ~17 cm and a mass of 7.53 kg. The expected mission design life is 5 years.
Table 1: Mission parameters of BLITS
Launch: BLITS was launched as a secondary payload to the Meteor-M-1 mission on Sept. 17, 2009. The launch vehicle was a Soyuz-2.1b/Fregat, and the launch site was the Baikonur Cosmodrome in Kazakhstan.
Orbit: Sun-synchronous near-circular orbit, mean altitude of 832 km, inclination = 98.85º, period of 101.3 minutes, local equatorial crossing time at 12:00 hours.
A special-purpose separation system provides spinning of the BLITS satellite after its separation from the Meteor – M-1 spacecraft at a rate of more than 6 (possibly 10 – 20) rpm around the axis normal to its orbit plane, thus providing optimum conditions for observation from the Earth. The reflected signal will thereby consist of regular “bursts” of return pulses, with a “burst” duration nearly equal to one half of the satellite spin period.
The expected retroreflector cross-section of the BLITS nanosatellite is approximately 100, 000 m3 at λ = 532 nm.
Figure 2: Illustration of the BLITS separation system (image credit: IPIE, Ref. #
Status of mission:
• BLITS appears to have been struck by space debris in January 2013. 5)
A piece of space debris, left over from the 2007 Chinese missile test, could have collided with BLITS in January 2013. The space collision appears to have occurred on Jan. 22, 2013, when a chunk of China's FY-1C (Feng Yun-1C) satellite, which was intentionally destroyed by that country in a 2007 anti-satellite demonstration, struck the Russian spacecraft, according to an analysis by CSSI (Center for Space Standards & Innovation) in Colorado Springs, CO, USA.
The CSSI technical program manager T. S. Kelso reported, that the collision involved the Chinese space junk and Russia's small BLITS (Ball Lens In The Space) retroreflector satellite of 7.5 kg.
Evidence of the space junk collision was first reported on Feb. 4, 2013 by the Russian scientists Vasiliy Yurasov and Andrey Nazarenko, both with IPIE (Institute for Precision Instrument Engineering) in Moscow. They reported a "significant change" in the orbit of the BLITS satellite to the CSSI. — The scientists estimated the change happened on Jan. 22. They contacted Kelso because CSSI operates a service that looks for close satellite approaches. CSSI looked for objects that may have had a nearby approach with the BLITS nanosatellite around the time of the collision. The Chinese debris was the only object they found. 6)
It is not immediately clear whether the satellite is merely wounded or completely incapacitated.
• BLITS is the first satellite designed as a spherical retroreflector for SLR. The body has a clear symmetry axis around which the mass of the transparent and coated hemispheres is distributed. During the deployment, the separation system made the satellite spin around an axis almost perpendicular to the symmetry axis of the body.
Measurements of the Graz 2 kHz SLR station during the period Sept. 26, 2009 to Nov. 24, 2010 indicate, that the spin parameters of the nanosatellite were not stable after the launch. The initial, very dynamic, change of the spin axis orientation could be caused by a direct action of the deployment mechanism or by the influence of Earth’s gravity field, due to an offset between the geometrical center and the center-of-mass of the satellite. 7)
1) “BLITS,” ILRS, NASA, URL: http://ilrs.gsfc.nasa.gov/missions/satellite_missions/current_missions/blit_general.html
2) V. D. Shargorodsky, V. P. Vasiliev, S. B. Novikov, A. A. Chubykin, N. N. Parkhomenko, M. A. Sadovnikov, “Progress in Laser Systems for Precision Ranging, Angle Measurements, Photometry, and Data Transfer,” ILRS Fall 2007 Workshop, Sept. 25-28, 2007, Grasse, France, URL: http://www-g.oca.eu/.../9_Session.pdf/9.4_Vasiliev_ProgressSLR_and_Others.pdf
3) V. B. Burmistrov, N. N. Parkhomenko, Y. A. Roy, V. D. Shargorodsky, V. P. Vasiliev, J. J. Degnan, S. Habib, V. D. Glotov, N. L. Sokolov, “Spherical Retroreflector with an Extremely Small Target Error: International Experiment in Space,” URL: http://cddis.nasa.gov/lw13/docs/papers/target_vasiliev_1m.pdf
5) Leonard David, “Russian Satellite Hit by Debris from Chinese Anti-Satellite Test,” Space.com, March 8, 2013, URL: http://www.space.com/20138-russian-satellite-chinese-space-junk.html
6) T. S. Kelso, “Chinese space debris hits Russian satellite,” AGI, March 8, 2013, URL: http://blogs.agi.com/agi/2013/03/08/chinese-space-debris-hits-russian-satellite/
7) D. Kucharski, G. Kirchner, F. Koidl, “Spin parameters of nanosatellite BLITS determined from Graz 2 kHz SLR data,” Advances in Space Research, Vol. 48, Issue 2, 15 July 2011, pp. 343–348
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.