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Front End Service Vehicle (FESV)
Two Front End Service Vehicles (FESV), designed and manufactured in Taiwan, have been delivered to Chile and passed acceptance tests by August 30 and December 14, respectively at the ALMA operation site of 5000 meter height in Chile. Reports about the site acceptance for the two FESVs are given below.
The PAS for the FESV1 was carried out successfully on August 29-30, 2011 at OSF in Chile. FESV1 made it up to the AOS on Aug. 29. It was loaded with a Dummy FE on a prototype FEHV and we had the Working Cabin HVAC running, set at 18 degrees (antenna receiver cabin temperature). At the AOS we also switched on the cryogenics equipment to check the capacity of the on-board generator at 5000m. Data logging equipment for inside and outside temperatures and FE shock and vibration monitoring were installed too. The trip up to AOS took a little over one hour and the return trip 45 minutes. The 26 ton truck has enough power to easily maintain the ALMA top speed limit of 40 km/h at all inclines and altitudes. The engine brake/retarder combination allowed for descending without ever touching the main brakes. Truck and generator together consumed 77L diesel for the 65 km travelled. At the AOS we successfully docked on to a Melco 12m antenna, which has the most challenging envelope to dock on to. The weather was cold with wind speeds up to 19 m/s. But as with the 7m antenna checked the day before, the scissor/outrigger design showed a remarkable resistance against wind gusts. It can be stated that the FESV will certainly not limit the array operations due to wind conditions. The figures below show the dummy FE carried by the prototype FEHV heading to the antenna through the docking bridge of FESV1 at high site.
Figure 1. Left: FEHV crossing the bridge of FESV1. Right: FESV2 working at AOS.
The PAS for FESV2 was carried out on December 13-14 at OSF and AOS. The review panel approved the PAS with conditions. The action items for FESV2 to be followed-up are: (1) To replace the oil pump of the tailgate for the FESV1 which has a leakage problem. (The vender will provide a new pump and ship to Chile without extra charge). (2) To replace one defective sensor of the three auto-leveling sensors on FESV2. (3) To modify the contents of the maintenance and operation manuals according to the comments of the review panel. Here below are the pictures showing the FESV1 & 2 operating on site.
Figure 2. Left: FESV2 working at OSF. Right: FESV1 & FESV2 operating at AOS.
For more information about FESV, please access the press release provided by NRAO here.