# Presentation: 704585

***C.S. Jacobs***
**G. E. Lanyi, C.J. Naudet**
*JPL (Caltech/NASA)*
- 9 February 2004

***Is Now the Time to***
***Replace***
***S / X with X / Ka - band?***

** ****IVS General Meeting 2004**

## •  Motivation for a radio frame above 8 GHz (X-band)

• Initial Observations & Results

• Current X / Ka antennas

• Plans taking shape

• Proposed Roadmap for transitions from S/X to X/Ka

**•  ****Motivation for a radio frame above 8 GHz (X-band)**
**• ****Initial Observations & Results**
**• ****Current X / Ka antennas**
**• ****Plans taking shape**
**• ****Proposed Roadmap for transitions from S/X to X/Ka**

**Outline**

## Motivation

**• ****Astrometry, Geodesy and Deep Space navigation, **
**   ****now at 8.4 GHz (X-band)**
_**Going to Higher radio frequencies allows**_
**• ****More compact sources (*****Boboltz et al*****)**
**   ****thus more stable positions (*****Ma et al*****)**
**• ****Higher Telemetry Rates to Spacecraft**
**• ****Avoid 2.3 GHz RFI issues**
**	**
**• ****Ionosphere &**** ****solar plasma**** ****down 16X !!**
**  ****at 32 GHz (Ka-band) compared to 8 GHz.**

**Picture credit: SOHO/ESA/NASA**

## Why Ka-band?

- Murphy, R. et al., 1987, Earth Observing System Volume IIe: HMRR High-Resolution Multifrequency Microwave Radiometer.
- Published by NASA, Goddard Space Flight Centre, Greenbelt, Maryland 20771, USA, 59pp.

- The three curves show absorption
- in a dry atmosphere, in the same
- atmosphere with 20 kg/m2 of
- added water vapour, and with
- both water vapour and 0.2 kg/m2
- of stratus cloud added.
- .

***Valleys are microwave windows***

- Murphy, R. et al., 1987,
- Earth Observing System Volume IIe:
-  HMRR High-Resolution
- Multifrequency Microwave Radiometer.
- Published by NASA, Goddard Space Flight Centre,
-  Greenbelt, Maryland 20771, USA, 59pp.

## Game Plan

**• ****Long term - simultaneous 8.4 and 32 GHz (X/Ka-bands)**
**	****at present instrumentation partially in place**
**• ****Interim plan: Bracket 32 GHz with currently available**
**	****24 GHz (K-band)**
**	****43 GHz (Q-band)**
**	****- Interpolate behavior at 32 GHz (Ka-band)**
** ****	****   ****Boboltz et al --> imaging**
**	****   ****Ma et al        --> astrometry & geodesy**
**• ****Done: Deep Space network: 4 antennas California & Spain**
**• ****Deep Space Network plans**
**	****Goldstone-Spain         2004 February**
** ****	****Goldstone-Australia   2005 April**
**	****VLBA                          2005?? Later??**
**• ****Exploring potential Goldstone CA to Kashima**

## Initial Observations: 24 (>>32<<) 43 GHz

**Initial Observations: 24 ****(>>32<<)**** 43 GHz**

**• ****VLBA ten 25m antennas**
**• ****Observing at 24 & 43 GHz**
**  ****for global astrometry/geodesy**
**  ****since May 2002**
** ****--> ****brackets Ka-band (32 GHz)**
**• ****Interpolating 24, 43 to 32 GHz**
**  ****demonstrates sources have**
**  ****1) sufficient flux**
**  ****2) Dense enough coverage**
**  ****3) More compact than X-band**

**(photos credit NRAO/NSF/AUI  **http://www.aoc.nrao.edu/vlba/html/vlbahome/thesites.html**)**

## First Ka-band Fringes !

**2001  Sept. 30th**
**DSS 13-DSS 25**
- Goldstone, CA
**10km CEI**
** ****32.036 GHz**
**Source = DA 55**
***SNR = 166***

## Deep Space Network Roadmap

_**Station Site             Ka/X installed**_
**DSS 13 Goldstone  2001**
**DSS 25 Goldstone  2001**
**DSS 26 Goldstone  2003 April**
**DSS 55 Madrid****	****    2003 November**
**DSS 34 Tidbin.       2005 April**
**DSS 24 Goldstone  2006 October**
**DSS 54 Madrid      2007 August**
***• ******Seven (7) antennas in place***
***  ******NOW or with firm plans!!***

***Goldstone, California***
***DSS 24, DSS 25, and DSS 26***
***34m Beam-waveguide antennas***
***(Apollo sub-site)***

## VLBA Roadmap?

**• ****Desire to equip all ten (10) VLBA antennas**
**   *****simultaneous***** X (8.4 GHz) / Ka (32 GHz)**
**• ****Dream: VLBA by time of Mars ‘05 mission.  Reality TBD**
**• ****Solid technical interest from NASA code S**
**•  ****Motivation to extend ICRF to X/Ka as soon as possible (!)**
**   ****in order to support Ka-band spacecraft navigation**
**• ****Talks in progress with NRAO regarding technical issues**
**   ****feed design, placement, etc.**
**• ****Talks in progress amongst NASA, NRAO, NSF**
**   ****$eeking to identify funding**

## Kashima, Japan

**Kashima, Japan already has Ka-band !**
**      ****34m antenna**
**      ****Tsys ~ 150 Kelvin**
**      ****31. 7 to 33.7 GHz**
**Ka-band since circa 2002**
**Potential collaboration with NASA?**

## Conclusions

**• *****NOW***
**   **
**  *****ICRF extended to 24 and 43 GHz  at sub-mas accuracy !***
**	****25 sessions: 230, & 108 sources, respectively**
**  ****Four (4) DSN antennas equipped with X/Ka**
**  ****Kashima, Japan Ka-band (single band)**
**• *****Future Plans***
**	****All 3 DSN complexes by April ****	****2005**
**              ****Seven (7) DSN antennas by   ****	****2007**
**	**_**Ten (10) VLBA proposed**__**	**__**2005??**_
**              ****Eighteen (18) antennas in place or being considered!!!**
**              *****Your antenna by ??*****	****	**

## We Want to Invite You Aboard !

**All are **
**Welcome**
**as we**
**travel **

**On to**
- X/ Ka
**Land !**