1. SITR April 2009; Page 1 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR GREAT GREAT: German REceiver for Astronomy at Terahertz frequencies PI-Instrument funded and developed by  MPIfR (2.7THz channel)  R. Güsten (PI)  S. Heyminck (system engineer)  B. KIein (FFT spectrometer)  MPIfR Engineers (electronics, LO-mechanics)  KOSMA (1.4/1.9THz channels)  J. Stutzki (Co-PI)  U.U. Graf et al. (1.4 &1.9THz LO, Optics)  K. Jacobs et al. (mixers @1.9THz & 2.7THz)  R. Schieder et al. (array-AOS)  DLR-Berlin (4.7THz channel)  H-W Hübers et al. (IF, cold-Load, …)  MPS  P. Hartogh et al. (CO-PI; CTS) Lab-picture of GREAT equipped with theL#1 and L#2 channel

2. SITR April 2009; Page 2 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Early-Science Configurations GREAT flight configurations:  baseline: simultaneous observations with 2 low-frequency channels  goal: fly mid-frequency channel at the earliest possible (altitude)  upgrade : operate 4.7 THz channel (not in short and basic science) Short science configuration:  baseline configuration (2 low-frequency channels) Basic science configuration:  goal configurations (combinations of the mid and low-frequency channels) request pending for schedule adjustment with envelope expansion prior to GREAT SS flights

3. SITR April 2009; Page 3 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Stoplight-chart ongoing project schedule delays  pose incalculable risk on integrity of GREAT project  funding at risk, more than ever  loosing support of interested G communities  science return of “investment” unpredictable for consortium  planning of instrument developments vs. other projects is impossible  how to restore confidence in stability of project schedule ?  not communicated well  delay of almost one year came by surprise (old schedule was confirmed at PSR in Dec. 2008) Comments:  M-Band Solid-State-LO technical risk (not short science) GREAT L-L configuration passed its PSR in Dec. 2008 and is ready for shipment SOFIA schedule

4. SITR April 2009; Page 4 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR GREAT in L-L configuration Power distributor Monitor drawler Ethernet-HUB Obs-computer IF-Power-supply IF Pre-processor IF LO-supply IF-processor Chopper control SOFIA PI-rack AOS-system CTS #1 and #2 FFTS (see talk W4D) Oscilloscope LO-synthesizer #1 Optics control Instrument computer Mixer-BIAS #1 & #2 Power-supply LO-synthesizer #2 1.9 THz Solid-state LO 1.4 THz Solid-state LO Cryostats SI mounting flange Cold-load Picture taken by DLR

5. SITR April 2009; Page 5 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Software frontend software  allows fully remote hardware access  offers  a debugging GUI monitoring all software tasks  an online database storing all available house- keeping data  a user GUI for easy instrument handling  a KOSMA file I/O interface  a Perl interface for individual hardware programming  a hardware simulation mode for development and debugging  well tested during the PSR-tests Obs-Software “KOSMA-control”  in use at KOSMA and Nanten II  well tested and understood

6. SITR April 2009; Page 6 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Cart GREAT Cart  fulfills all ICDs

7. SITR April 2009; Page 7 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Ready for Shipment GREAT was ready for shipment by end of February as required to meet the last project schedule  customized shipping boxes available  main-structure + cart + LOs  four boxes for cryostats  aluminum boxes for electronics/ tools Picture: GREAT main structure shipping box waiting to be stored

8. SITR April 2009; Page 8 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR L#2: performance goody Best noise-performance we measured so far ! uncorrected receiver noise performance measured at 1821GHz LO frequency

9. SITR April 2009; Page 9 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Ongoing developments  increase usable RF-bandwidth  new HEB-mixer  new cold amplifier with better matching to the mixer  no isolator required (isolator is limiting bandwidth so far)  first tests are currently ongoing in Cologne  build-up of the M-band channel (2.7THz)  optics and cryostat are ready  LO under development

10. SITR April 2009; Page 10 MPIfR KOSMA MPS DLR-Berlin S. Heyminck, MPIfR Schedule towards S/S flights Schedule counts backwards from first science flight date: start of GREAT short science period (end of May 2010) -4 weeksschedule reserve to solve unexpected problems -2 weeks install GREAT, EMI-test, line-Obs -4 weeksschedule reserve to solve unexpected problems -2 weeksre-integration and post shipment inspection -1 weeksschedule reserve for delays during shipment -2 weeksshipping the instrument to Palmdale -1 weeksde-integration and packing -8 weeks pre-shipment testing (e.g. test new mixers) (in total 24 weeks)