diff --git a/components/isceobj/Sensor/TOPS/Sentinel1.py b/components/isceobj/Sensor/TOPS/Sentinel1.py
index 52145d5..fc8b640 100755
--- a/components/isceobj/Sensor/TOPS/Sentinel1.py
+++ b/components/isceobj/Sensor/TOPS/Sentinel1.py
@@ -40,7 +40,6 @@ from .BurstSLC import BurstSLC
 from isceobj.Util import Poly1D, Poly2D
 from isceobj.Planet.Planet import Planet
 from isceobj.Orbit.Orbit import StateVector, Orbit
-from isceobj.Orbit.OrbitExtender import OrbitExtender
 from isceobj.Planet.AstronomicalHandbook import Const
 from iscesys.Component.Component import Component
 from iscesys.Component.ProductManager import ProductManager
@@ -822,12 +821,8 @@ class Sentinel1(Component):
 
         #####Orbits provided in annotation files are not InSAR-grade
         #####These also need extensions for interpolation to work
-        orbExt = OrbitExtender(planet=Planet(pname='Earth'))
-        orbExt.configure()
-        newOrb = orbExt.extendOrbit(frameOrbit)
 
-
-        return newOrb
+        return frameOrbit
             
     def extractPreciseOrbit(self, margin=60.0):
         '''
diff --git a/components/isceobj/TopsProc/runFineResamp.py b/components/isceobj/TopsProc/runFineResamp.py
index d1c1ad0..1955a94 100755
--- a/components/isceobj/TopsProc/runFineResamp.py
+++ b/components/isceobj/TopsProc/runFineResamp.py
@@ -127,7 +127,7 @@ def adjustValidSampleLine(master, slave, minAz=0, maxAz=0, minRng=0, maxRng=0):
             else:
                master.numValidSamples = master.numberOfSamples - master.firstValidSample
 
-
+    master.firstValidSample = np.max([0, master.firstValidSample])
     ###Adjust valid lines and first valid line here
     print ("Adjust valid lines")
     print('Before: ', master.firstValidLine, master.numValidLines)
diff --git a/contrib/stack/topsStack/s1a_isce_utils.py b/contrib/stack/topsStack/s1a_isce_utils.py
index 2f793a8..bd082e2 100755
--- a/contrib/stack/topsStack/s1a_isce_utils.py
+++ b/contrib/stack/topsStack/s1a_isce_utils.py
@@ -141,6 +141,8 @@ def adjustValidSampleLine_V2(master, slave, minAz=0, maxAz=0, minRng=0, maxRng=0
         else:
             master.numValidSamples = master.numberOfSamples - master.firstValidSample
 
+    master.firstValidSample = np.max([0, master.firstValidSample])
+ 
     print('After: ', master.firstValidSample, master.numValidSamples)
 
     ###Adjust valid lines and first valid line here